VO Fresh

Relative magnetic fields of 3 M dwarfs

2026-04-11T13:07:36Z

Description: Setting observational constraints on stellar magnetic fields is essential for both stellar and planetary physics. They play a key role in the formation and evolution of stars and planets, and they are responsible for spurious signals in radial velocity curves that impact the detection and characterization of exoplanets. Recent observations have revealed the diversity and evolution of large-scale magnetic fields in low-mass stars. However, these large-scale fields only account for a small fraction of the observed unsigned magnetic flux. The other crucial stellar magnetism information originates from (spatially) small-scale magnetic fields, which account for most of the surface magnetic flux and exhibit a clear temporal evolution on timescales of many years. With this work, we aim to develop new fast techniques to extract small-scale magnetic field estimates from time series of observed high-resolution spectra. One objective is to develop tools that will enable the community to take full advantage of the upcoming monitoring surveys carried out with various high-resolution spectrometers. Our ultimate goal is to study the temporal evolution of small-scale magnetic fields and offer insights into the magnetic properties of low-mass stars and their magnetic cycles. We implemented a process to capture relative pixel variations caused by changes in magnetic field strengths, relying on synthetic spectra computed with ZeeTurbo. This approach provides extremely fast and reliable estimates of relative magnetic field strength variations from series of high-resolution spectra, mitigating the impact of systematics between models and observations. We assessed the performance of the proposed method through its application to simulated data and publicly available observed spectra recorded with SPIRou, Narval, and ESPaDOnS. In addition, we implemented a model-driven process to derive relative temperature variations and we explored the influence magnetic fields have on these measurements. Our results are in excellent agreement with the magnetic field estimates previously obtained from spectra recorded with SPIRou. This method provides robust constraints on the structure of the magnetic field variations and proves to be relatively insensitive to small changes in the assumed atmospheric parameters and broadening. We find that magnetic field variations have the potential of introducing biases in relative temperature estimates. This is particularly relevant in the case of the Narval/ESPaDOnS spectral domains, which contain a large number of magnetically sensitive transitions and where contrast is more important. Our application to archival data provides new constraints on the evolution of small-scale magnetic fields and underscores the potential of the proposed method for analyzing data in the context of large observation programs. By reducing the problem to a set of linear equations, our method offers extremely fast results, making it viable for integration in future pipelines developed for large spectroscopic surveys. These estimates will provide much needed information to correct radial velocity curves and constrain dynamo processes.
Author(s): Cristofari P.I.; Saar S.H.; Vidotto A.A.; Bellotti S.
IVOA id: ivo://cds.vizier/j/a+a/708/a207

Apertif DR2 - HI spectral cubes

2026-04-10T15:23:43Z

Description

Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. A description of the second data release is to be
included here. This service queries the spectral line cubes from the
second data release of Apertif. Four line cubes are produced over a
set of different frequency ranges as follows. Cube 0:  1292.5–1337.1
MHz, Cube 1: 1333.1–1377.7 MHz, Cube 2: 1373.8–1418.4 MHz, Cube 3:
1414.5–1429.3 MHz. Cube 3 is produced at full spectral resolution of
12.2 kHz while other cubes are produced with a 3-channel averaging at
36.6 kHz resolution. The cubes have a spatial extent of 1.1 deg × 1.1
deg (661 × 661 pixels, with 6''/pixel). The median noise for all line
cubes, with a spectral resolution of 36.6 kHz, is 1.6 mJy/beam,
corresponding to a 3-σ H I column density sensitivity of 1.8 × 10^20
atoms cm^−2 over 20 km s^−1 (for a median angular resolution of 24″ ×
15″). The corresponding dirty beam cubes are also released to allow
offline cleaning of source emission.

Author(s)

Apertif Team

IVOA id

ivo://astron.nl/apertif_dr2/q/apertif_dr2_spectral_cubes

Apertif DR2 - Field raw visibilities

2026-04-10T15:23:43Z

Description

Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. A description of the second data release is to be
included here. The raw visibility data are provided as separate
collections for the survey fields, flux calibrator and polarization
calibrator observations. The tables can be joined to identify the
associated calibrators for a target observation. This service queries
the raw visibilities for the survey fields. These are stored on tape
and are not immediately available for download. The data release
documentation should be consulted for up-to-date information on how to
access the data.

Author(s)

Apertif Team

IVOA id

ivo://astron.nl/apertif_dr2/q/apertif_dr2_raw_visibilities

Apertif DR2 - Polarization cubes

2026-04-10T15:23:43Z

Description

Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. A description of the second data release is to be
included here. This service queries the polarization cubes from the
second data release of Apertif. In order to prevent bandwidth
depolarization and enable rotation measure synthesis studies, Stokes Q
and U cubes with a frequency resolution of 6.25 MHz are produced. The
cubes have a smaller spatial extent of 2.7 deg × 2.7 deg (2049 × 2049
pixels, with 4''/pixel ) than the continuum or Stokes V images but
still extend well beyond the primary beam.

Author(s)

Apertif Team

IVOA id

ivo://astron.nl/apertif_dr2/q/apertif_dr2_polarization_cubes

Apertif DR2 - Polarization calibrator raw visibilities

2026-04-10T15:23:43Z

Description

Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. A description of the second data release is to be
included here. The raw visibility data are provided as separate
collections for the survey fields, flux calibrator and polarization
calibrator observations. The tables can be joined to identify the
associated calibrators for a target observation. This service queries
the raw visibilities for the polarization calibrator. These are stored
on tape and are not immediately available for download. The data
release documentation should be consulted for up-to-date information
on how to access the data.

Author(s)

Apertif Team

IVOA id

ivo://astron.nl/apertif_dr2/q/apertif_dr2_pol_cal_visibilities

Apertif DR2 - Flux calibrator raw visibilities

2026-04-10T15:23:43Z

Description

Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. A description of the second data release is to be
included here. The raw visibility data are provided as separate
collections for the survey fields, flux calibrator and polarization
calibrator observations. The tables can be joined to identify the
associated calibrators for a target observation. This service queries
the raw visibilities for the flux calibrator. These are stored on tape
and are not immediately available for download. The data release
documentation should be consulted for up-to-date information on how to
access the data.

Author(s)

Apertif Team

IVOA id

ivo://astron.nl/apertif_dr2/q/apertif_dr2_flux_cal_visibilities

Apertif DR2 - Field calibrated visibilities

2026-04-10T15:23:43Z

Description

Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. A description of the second data release is to be
included here. This service queries the calibrated visibility
measurement sets. The calibrated visibility data, with
cross-calibration and self-calibration solutions applied, are
currently stored as an intermediate data product at full time and
spectral resolution. These are stored on tape with the raw data and
are not immediately available for download. The data release
documentation should be consulted for up-to-date information on how to
access the data.

Author(s)

Apertif Team

IVOA id

ivo://astron.nl/apertif_dr2/q/apertif_dr2_calibrated_visibilities

Apertif DR2 - Continuum images

2026-04-10T15:23:43Z

Description

Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. A description of the second data release is to be
included here. This service queries the continuum images from the
second data release of Apertif. Multi-frequency synthesis (mfs) Stokes
I images are produced over the full frequency range (1292.5– 1430 MHz)
and saved as fits files for each beam. The size of the continuum
images is 3.4 deg × 3.4 deg (3073 × 3073 pixels, with 4''/pixel). The
median noise in the continuum images is 41.4 uJy/beam and the median
angular resolution is 11.6''/sin(declination). A companion VO table
provides a continuum source catalog based on all continuum images
contained in this data release and is described in Kutkin et al.
(2022) (see
https://vo.astron.nl/apertif_dr2/q/apertif_dr2_catalogue/form).

Author(s)

Apertif Team

IVOA id

ivo://astron.nl/apertif_dr2/q/apertif_dr2_continuum_images

Deblended MIGHTEE-COSMOS radio catalogues

2026-04-10T13:42:42Z

Description: Deep radio continuum surveys provide fundamental constraints on galaxy evolution, but source confusion limits sensitivity to the faintest sources. We present a complete framework for producing high-fidelity deblended radio catalogues from the confused MIGHTEE maps using the probabilistic deblending framework XID+ and prior positions from deep multi-wavelength data in the COSMOS field. Applied to the ~1.3deg^2^ area of the MIGHTEE-COSMOS field, this procedure yields a deblended catalogue of 89,562 sources. We also define a recommended high-fidelity sample of 20757 sources, based on detection significance, flux density, and goodness-of-fit.
Author(s): Malefahlo E.; Jarvis M.J.; Santos M.G.; Cress C.; Smith D.J.B.; Hale C.L.,Afonso J.; Whittam I.H.; Vaccari M.; Heywood I.; Jin S.; An F.
IVOA id: ivo://cds.vizier/j/mnras/547/g285

Extinction distances for planetary nebulae

2026-04-10T08:18:30Z

Description: Although Gaia has identified the central stars of planetary nebulae (CSPNe) for about 70% of known Galactic planetary nebulae (PNe), reliable distance estimates remain highly incomplete, with fewer than one quarter having accurate parallaxes. Mean-while, the classical extinction-distance sample has long been limited to about 70 objects, accounting for only 1.8 of the Galactic PNe population. We aim to obtain a large and homogeneous catalogue of PN distances by refining extinction-distance measurements with Gaia DR3, providing a complementary method to CSPN-parallax-based distances. We developed a Gaia-based extinction-distance method for PNe by combining an improved blue-edge approach with an extinction-jump model. Planetary nebula distances were inferred from stellar extinction jumps in line-of-sight extinction-distance profiles and constrained by comparisons with published distances, stellar spatial distributions relative to the PN centre, and the PN radius-distance relation. We obtain distances for 1066 PNe, with a median relative uncertainty of 13% and below 20% for about 87% of the sample. This sample includes 765 objects whose CSPN parallaxes have relative uncertainties greater than 20% and 128 objects without CSPN parallaxes. Our method not only complements CSPN parallax-based approaches for PN distance determination but also extends the traditional extinction-based approach to higher Galactic latitudes. In cases where published distance estimates for the same PN differ significantly, the method helps identify the more reliable distance. In addition, it helps evaluate the reliability of CSPN identifications. We find a likely misidentification in the reported CSPN for Fr2-36, and further analyse 33 PNe with two different CSPNe identifications, suggesting a more suitable CSPN for 15 objects. The resulting catalogue is the largest homogeneous set of extinction-based PN distances to date and provides a robust benchmark for studies of Galactic structure, PN populations, and interstellar extinction.
Author(s): Deng J.; Wang S.; Jiang B.; Deng L.
IVOA id: ivo://cds.vizier/j/a+a/708/a191

Morphological stability of open clusters

2026-04-09T17:34:21Z

Description: Open clusters (OCs) usually evolve gradually as the number of their members changes, which can be manifested in their morphological characteristics. Therefore, the morphological study of OCs lays the foundation for a better understanding of their formation and evolutionary processes. We aim to investigate the morphological stability of 1490 OCs and further explore the potential change of morphological stability of the OCs at different spatial positions, using the OC catalog from the literature. We delineate the two-dimensional (2D) morphology of OCs quantitatively in the projection perpendicular to the Galactic disk plane by the rose diagram and analyze the slope changes between the morphological stabilities (Score/Souter and Ncore/Nouter) and the number of members (N) within tidal radii to investigate the influence of the external environment on the OCs at different spatial positions. We define for the first time a new morphological stability parameter Ncore/Nouter, a ratio of member numbers between cluster core and outer areas within tidal radii, which has a significant positive correlation against N, with a slope of 1.140+/-0.039, significantly steeper than the 0.720+/-0.026 measured for Score/Souter . This demonstrates that the stellar density in the core is a more sensitive tracer for morphological stability than geometry. Spatially, the radial sample OCs have larger slopes of Ncore/Nouter and Score/Souter against N, with 1.083+/-0.116 and 0.733+/-0.080, respectively, whereas those in the tangential direction 1.013+/-0.110 and 0.529+/-0.075, respectively, which means that the impact on sample OCs from tidal forces directed toward the Galactic center is possibly stronger than that from the shear force caused by the differential rotation of the Galactic disk. Moreover, the sample OCs within 90{deg} of the Galactic center, closer to the bar, exhibit slopes below 0.6 of Score /Souter against N, indicating heightened external perturbations and diminished stability. But the opposite is true for the side greater than 90{deg}. Thus, this illustrates that the influence of the external environment on our sample OCs is asymmetrical. Besides, the sample OCs younger than 30Myr display a shallow slope of 0.751+/-0.166, with those older than 800Myr (1.442+/-0.128), reflecting that young OCs likely endure both internal disruptions, such as early dynamical heating weakening core binding and more severe external disturbances, compared to older OCs. The morphological stability of OCs is not only determined by their gravitational binding, but also strongly modulated by the external environment in which they are located.
Author(s): Li Y.; Hu Q.; Cai Y.; Dai Y.; Qin M.; Luo Y.
IVOA id: ivo://cds.vizier/j/a+a/708/a238

GJ 1137 RVs and activity indices

2026-04-09T17:33:06Z

Description: Detection and characterisation of Jovian analogues in precision radial velocity (RV) measurements is gaining momentum due to the constantly increasing observational baseline of Doppler surveys. The occurrence rate of Jovian-mass exoplanets is crucial for understanding the architecture of planetary systems. However, long-period RV signals in Doppler surveys could also be induced by stellar magnetic cycles, leading to misinterpretations of planetary candidates. We investigate the long-term RV variability in the K-dwarf star GJ1137 (HD93083, HIP52521), a known Saturn-mass exoplanet host, and assess the role of stellar activity in shaping the observed signals. We analyse 13 years of archival high-precision spectroscopic observations obtained with the High Accuracy Radial velocity Planet Searcher spectrograph (HARPS). We performed an extensive spectroscopic analysis of the stellar activity indicators and applied an RV modelling approach, incorporating Keplerian fits, Gaussian process regression as a proxy for stellar activity, and other stellar activity diagnostics. Furthermore, we refined the orbital parameters and the minimum mass of the known exoplanet GJ 1137 b and searched for additional planetary candidates in the system. We detect a long-period RV signal that, if interpreted as planetary, would suggest the presence of a Jovian-analogue companion. However, our spectroscopic activity analysis provides strong evidence that this variability is induced by the star's long-term magnetic cycle P_cyc_=5870^+480^_-350_ days rather than by an orbiting planet. The signal is detected in both the full width at half maximum (FWHM) of the cross-correlation function and the chromospheric activity index logR'_HK. We measure the stellar rotation period to P_rot_=32.3^+1.2^_-1.3_ days and identify a significant short-period RV signal, which we attribute to a Super Earth with a period of 9.6412^+12^_-11_ days and a minimum mass of 5.12^+0.70^_-0.69_ Earth masses, making GJ 1137 a multiple-planet system.
Author(s): Stoeva D.; Stefanov A.K.; Stefanov S.Y.; Lafarga M.; Bebekovska E.V.,Filomeno S.; Gonzalez-Hernandez J.I.; Suarez-Mascareno A.; Rebolo R.,Nari N.; Mestre J.M.; Antonova D.; Zaharieva E.; Bozhilov V.; Trifonov T.
IVOA id: ivo://cds.vizier/j/a+a/708/a232

Stellar age determination using deep NN

2026-04-09T16:28:35Z

Description: Recent spectroscopic surveys provide element abundances for large samples of Milky Way stars, from which stellar parameters can be inferred. Stellar ages, among them, are both a notoriously difficult parameter to estimate and a fundamental property for Galactic archaeology studies. We aim to develop a model-driven deep learning approach to age determination, by training neural networks on stellar evolutionary grids. Contrary to the usual data-driven deep learning approach of using prior age estimates as training data, our method has the potential for a wider and less biased range of application. The low computational cost of deep learning methods compared to e.g., bayesian isochrone-fitting allows for a broad analysis of large spectroscopic catalogues. We train multilayer perceptrons on different stellar evolutionary grids to map [M/H], M_G_, (G_BP_-G_RP_) to stellar age tau. We combine Gaia photometry and parallaxes, metallicities and alpha elements from spectroscopic surveys and extinction maps, which are passed through the neural networks to estimate stellar ages. We apply our method to the LAMOST DR10, GALAH DR3 & DR4 and APOGEE DR17 spectroscopic surveys, for which we estimate the ages using the BaSTI tracks, along with other stellar evolutionary models. We leverage this novel technique to study, for the first time, differences in age estimates from several evolutionary grids applied on very large datasets. In addition, we date 13 open clusters and one globular cluster and find a median absolute deviation with literature ages of 0.20Gyr. Along with the stellar ages catalogues from our estimates, we release NEST (Neural Estimator of Stellar Times), a python package to estimate stellar age based on this work and available at https://github.com/star-age/NEST, as well as a web interface https://star-age.github.io. We show that, when using the same evolutionary grid, our method retrieves the same ages as a bayesian approach like SPInS, for only a fraction of the computational cost, with a 60000 speedup factor for a typical star. This model-driven deep learning technique thus opens up the way for broad galactic archeology studies on the largest datasets available today and in the near future with upcoming surveys such as 4MOST.
Author(s): Boin T.; Casamiquela L.; Haywood M.; Di Matteo P.; Lebreton Y.; Uddin M.,Reese D.
IVOA id: ivo://cds.vizier/j/a+a/708/a215

HTRU-North pulsar survey. III

2026-04-09T16:20:08Z

Description: We continued the search for single pulses (SPs) in the northern part of the all-sky High Time Resolution Universe survey, whose aim is to detect pulsars and other radio transients. This search is now about 21% complete and yielded the first discovery of a fast radio burst (FRB) with the 100m Effelsberg Radio Telescope. FRB 20110220A is detected with an S/N optimised dispersion measure of 501.0pc/cm^3^ and width of 11.9+/-3.5ms giving it a fluence of 0.6+/-0.1Jy.ms. We obtained the first the first L-band detection of the rotating radio transient (RRAT) J2028+28, from which upper limits on the source's period and burst rate are obtained, as well as an improved position. The discovery of a new RRAT, J0404+53, is reported previously identified as an isolated SP candidate by Houben et al. (2026A&A.707A..10H, Cat. J/A+A/707/A10). Eight new SP trains and 272 faint isolated SP candidates were detected. The latter could be used to show the presence of a Galactic latitude and longitude dependence on the all-sky detection rates of the isolated SP candidates. This direction dependence suggests the existence of a faint Galactic SP population.
Author(s): Houben L.J.M.; Falcke H.; Spitler L.G.; Barr E.D.; Berezina M.,Champion D.J.; Karuppusamy R.; Kramer M.
IVOA id: ivo://cds.vizier/j/a+a/708/a199

Three new transiting warm Jupiters RV curves

2026-04-09T16:18:27Z

Description: We report the discovery and characterisation of three transiting warm Jupiters: TIC 147027702b, TIC 245076932b and TIC 87422071b. These systems were initially identified as transiting candidates using light curves generated from the full-frame images of the TESS mission. We confirmed the planetary nature of these objects with ground-based spectroscopic follow-up observations using FEROS and the new PLATOSpec spectrograph attached to the ESO 1.52m telescope at the La Silla Observatory, and with ground-based photometric observations of the Observatoire Moana, Las Cumbres Observatory Global Telescope and ASTEP. From a global fit to the photometry and radial velocities, we determine that the planet TIC 147027702b has a low-eccentric orbit (e=0.13+/-0.05) with a period of 44.4 days and has a mass of 1.09^+0.07^_-0.13_M_J_ and a radius of 0.98+/-0.06R_J_. TIC 245076932b has a moderately low mass of 0.51+/-0.05M_J_, a radius of 0.97+/-0.05R_J_, and an eccentric orbit (e=0.43+/-0.02) with a period of 21.6 days. TIC 87422071b has a mass of 1.29+/-0.10M_J_, a radius of 0.97+/-0.08R_J_, and has a slightly eccentric orbit (e=0.12+/-0.07) with a period of 11.3 days. These well-characterised warm Jupiters expand the currently limited sample of similar gas giants and provide valuable benchmarks for testing models of giant-planet formation, migration, and tidal evolution.
Author(s): Gajdos P.; Brahm R.; Acuna-Aguirre L.; Jones M.I.; Salinas H.; Liptak J.,Jordan A.; Henning T.; Srba J.; Zdarska E.; Balkoova Z.; Vitkova M.,Janik J.; Skoda P.; Zak J.; Mekarnia D.; Suarez O.; Abe L.; Beltrame M.,Triaud A.H.M.J.; Guillot T.; Collins K.A.; Barkaoui K.; Boyle G.; Suc V.,Antonucci L.; Tala Pinto M.; Vostretcova E.; Eberhardt J.; Espinoza N.,Mireles I.; Pintr P.; Rojas F.I.; Schaffenroth V.; Vanzi L.; Kabath P.
IVOA id: ivo://cds.vizier/j/a+a/708/a189

Robotic Bochum Twin Telescope (RoBoTT) images

2026-04-09T14:38:13Z

Description

The Robotic Bochum Twin Telescope (RoBoTT) operated from December
2008 to September 2019 at the Universitaetssternwarte Bochum near
Cerro Armazones in the Chilean Atacama desert. It consists of two
refractor telescopes (15 cm aperture, 2°42'' × 2°42'' FoV CCDs)
attached to the same mount. The fields were observed in Johnson UVBRI,
Sloan ugriz, and the narrowband OIII, NB, Halpha, and SII filters.

The first batch contains fields that were observed in Johnson U and
Sloan z; further RoBoTT fields will be added at a later date.

Bochum Galactic Disk Survey (BGDS) images, which were also taken with
the RoBoTT, are available separately from
ivo://org.gavo.dc/bgds/q/sia.

Author(s)

Blex, J.; Ramolla, M.; Westhues, C.; Demleitner, M.; Hackstein, M.; Chini, R.

IVOA id

ivo://org.gavo.dc/bgds/robott/sia

HECATEv2

2026-04-08T12:32:36Z

Description: We present HECATEv2, the second release of the Heraklion Extragalactic Catalogue (HECATE), an all-sky, value-added galaxy catalogue comprising 204733 galaxies from the HyperLEDA database with recession velocity <14000km/s (D~200Mpc). This release focuses on qualitative upgrades of the provided information while maintaining the same parent galaxy sample as HECATEv1. Improvements include a new cosmology-based distance framework, expanded and homogenised optical and mid-infrared photometry from SDSS-DR17/NSA, PS1-DR2, and AllWISE, and new quality-control flags for stellar contamination, incorrect photometry, and coordinate inconsistencies. We also extend the galaxy-size coverage and derive stellar population parameters for a substantially larger fraction of the sample. Star-formation rates (SFR) and stellar masses (Mstar) are now available for >70% of galaxies using updated mid-IR/optical calibrations that account for stellar population age and dust attenuation, while gas-phase metallicities are derived for ~90%. Activity classifications are provided for >50% of galaxies based on spectroscopic and/or photometric diagnostics, and supermassive black hole masses for ~86%. In terms of L_B_, L_Ks_, SFR, and Mstar , HECATEv2 is among the most complete local-Universe catalogues with spectroscopic redshifts. We also provide spatial completeness maps as a function of distance and luminosity, highlighting variations across the sky. Compared to other catalogues (e.g. GLADE+, NED-LVS), HECATEv2 offers broader (optical, near- and far-IR photometry, metallicity, activity classifications) or comparable (mid-IR photometry, SFR, Mstar) coverage, making it a robust reference for studies of SMBH-host galaxy connections, gravitational-wave and high-energy transient hosts, population analyses, and rare galaxy subpopulations.
Author(s): Kyritsis E.; Zezas A.; Kovlakas K.; Daoutis C.; Kouroumpatzakis K.,Hornschemeier A.; Basu-Zych A.
IVOA id: ivo://cds.vizier/j/mnras/548/g522

Physical properties of galaxies in MIRI/CEERS

2026-04-08T12:06:19Z

Description: The James Webb Space Telescope (JWST) enables the identification of quiescent galaxies (QGs) out to early epochs, offering a transformative view of their evolution. However, photometric selection of quiescent galaxy candidates (QGCs) and the derivation of their key physical quantities, such as stellar masses (M*) and dust attenuation, remain highly sensitive to the assumed star-formation histories (SFHs), where dust-age degeneracies and modelling choices remain a major source of uncertainty. We aim to quantify how the inclusion of JWST/MIRI data and different SFH models impacts the selection and characterisation of QGCs. We test the robustness of the physical properties inferred from the spectral energy distribution (SED) fitting, such as M*, age, star formation rate (SFR), and dust attenuation (AV), and study how they impact the quiescence criteria of the galaxies across cosmic time. We perform SED fitting for ~13000 galaxies at z<=6 from the CEERS/MIRI fields with <=20 optical-mid infrared (MIR) broadband coverage. We implement three SFH prescriptions: a flexible delayed, non-parametric, and an extended regulator model. For each SFH, we compare results obtained with and without MIRI photometry and dust emission models. We evaluate the impact of these configurations on both the number of QGCs, selected based on rest UVJ colours, sSFR and main-sequence offset, and on their key physical properties such as M*, AV, and stellar ages. The number of selected QGCs varies significantly with the choice of SFH ranging from 70 to 100, out of a mass-complete sample of ~5000 galaxies, depending on the model. This number increases to 103-180 when MIRI data are included, driven by improved constraints on both dust attenuation and M*. We find a strong correlation between AV and M* of QGCs at z<=2.5, with massive galaxies (M*~10^11^M_{sun}_) being ~1.5-4 times more attenuated than low-mass galaxies (M*~10^9^M_{sun}_). Regardless of the SFH, ~13% of QGCs exhibit significant attenuation (AV>0.5) in support of recent JWST results on dust-rich QGs.
Author(s): Lisiecki K.; Donevski D.; Man A.W.S.; Damjanov I.; Romano M.; Belli S.,Long A.; Lorenzon G.; Malek K.; Junais; Lovell C.C.; Nanni A.,Bertemes C.; Pearson W.; Ryzhov O.; Koprowski M.; Pollo A.; Dey S.,Thuruthipilly H.
IVOA id: ivo://cds.vizier/j/a+a/708/a235

AD Leo B light curve

2026-04-08T12:02:15Z

Description: Stellar flares are sudden brightenings caused by magnetic reconnection and are frequently observed on late-type stars. High-cadence photometry of flares provides valuable insights into the mechanisms of these events, yet such observations remain scarce. We seek to explore the sub-second fine structure of stellar flares and assess the information content in high-speed photometry. New 0.3 s-cadence photometry from a six-year-long observing campaign of the active M-dwarf AD Leo is presented. We use time-frequency analysis to detect quasi-periodic pulsations in the decay phase of flares. We explore statistical measures of time series complexity of the detected flares to quantify the information gain achievable with high-cadence photometry. We detect 42 flares in 211 hours of observations. The flare frequency distribution is consistent with the previous literature. We find no quasi-periodic pulsations with periods below a few seconds, and identify two candidate signals with periods around 1 and 3 min. Using different measures of complexity on the binned flare light curves we confirm the advantages of high observing cadence. However, we also find a plateau up to a binning of ~4-5s for a few complex flares, suggesting that an exposure time of a few seconds is usually enough to retain most of the information carried by a single-filter observation. New photometric observations of AD Leo revealed sub-structures of flare light curves on the timescale of a few seconds, but we found no features on timescales below that.
Author(s): Schmercz B.; Seli B.; Vida K.; Kriskovics L.; Gorgei A.; Olah K.; Regaly Zs.
IVOA id: ivo://cds.vizier/j/a+a/708/a225

XMM-Newton supervised flare detection

2026-04-08T12:00:56Z

Description: The EXTraS project, based on data collected with the XMM-Newton observatory, provided us with a vast amount of light curves for X-ray sources. For each light curve, EXTraS also provided us with a set of features (https://extras.inaf.it). We extract from the EXTraS database a tabular dataset of 31832 variable sources by 108 features. Of these, 13851 sources were manually labeled as stellar flares or non-flares based on direct visual inspection. We employed a supervised learning approach to produce a catalog of stellar flares based on our dataset, releasing it to the community. We leverage explainable AI tools and interpretable features to better understand our classifier. We train a gradient boosting classifier on 80% of the data for which labels are available. We compute permutation feature importance scores, visualize feature space using UMAP, and analyze some false positive and false negative data points with the help of Shapley additive explanations - an AI explainability technique used to measure the importance of each feature in determining the classifier's prediction for each instance. On the test set made up of the remainder 20% of our labeled data, we obtain an accuracy of 97.1%, with a precision of 82.4% and a recall of 73.3%. Our classifier outperforms a simple criterion based on fitting the light curve with a flare template and significantly surpasses a gradient-boosted classifier trained only on model-independent features. False positives appear related to flaring light curves that are not associated with a stellar counterpart, while false negatives often correspond to multiple flares or otherwise peculiar or noisy curves. We apply our trained classifier to currently unlabeled sources, releasing the largest catalog of X-ray stellar flares to date. We estimate that integrating our classifier into the astronomers' workflow will reduce the time spent visually inspecting light curves by approximately half compared to an approach based on flare template fitting, with implications for the classification of sources whose variability is less well established within EXTraS as well as for other catalogs and, possibly, forthcoming missions.
Author(s): Pasquato M.; Marelli M.; De Luca A.; Salvaterra R.; Carenini G.,Belfiore A.; Tiengo A.; Esposito P.
IVOA id: ivo://cds.vizier/j/a+a/708/a224

SN2025cbj LAST and ZTF photometric data

2026-04-08T11:59:25Z

Description: The origins of astrophysical high-energy neutrino flux remain uncertain. Core-collapse supernovae with strong CSM interaction (Type IIn a.k.a. SNe IIn) are compelling candidates for efficient hadronic acceleration and neutrino production. We investigate the possible association between the Type IIn supernova SN2025cbj and the IceCube high-energy neutrino IceCube-250421A, and assess whether the observed properties of the SN permit an appreciable neutrino yield. We combined rapid optical follow-up with LAST and archival ZTF photometry with spectroscopy from LT/SPRAT and MMT/BINOSPEC to characterize the SN's evolution and CSM interaction. We estimated the explosion and peak times from early light-curve fitting, and quantified the chance-coincidence probability with resampling simulations that scramble neutrino right ascensions while preserving declinations and error contours. Using a simple post-shock-breakout interaction model in a dense wind, we estimated the expected muon-neutrino yield for IceCube's real-time Bronze stream. Spectra of SN2025cbj obtained after the neutrino epoch show persistent narrow Balmer lines superposed on broad Lorentzian electron-scattering wings, consistent with sustained dense-CSM interaction. For the multi-messenger association, resampling simulations against the TNS catalog give a chance-coincidence probability for observing k>=1 events of p=~0.24 (and p=~0.078 against the ZTF-BTS catalog). These values are sensitive to the size of the SNe and neutrino samples. A post-breakout interaction scenario predicts an expected N{nu}{mu}~10^-3^ events in the IceCube Bronze alert stream over 76 days per this one candidate. We discuss the implications of these numbers and possible biases that may affect these results.
Author(s): Garrappa S.; Zimmerman E.A.; Wasserman T.; Ofek E.O.; Gal-Yam A.; Konno R.,Chen P.; Yaron O.; Ben-Ami S.; Copperwheat C.M.; Fainer S.; Horowicz A.,Humpe A.; Mazzali P.A.; Polishook D.; Segre E.; Spitzer S.A.
IVOA id: ivo://cds.vizier/j/a+a/708/a223

BASALT faint blazar candidates

2026-04-08T11:57:21Z

Description: We present a sample of blazar candidates from the Very Large Array Sky Survey (VLASS) catalog, with cross-referencing to optical and infrared data from the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) and the Wide-Field Infrared Survey Explorer (WISE), respectively. We focus on compact radio sources and employ a multistage selection process to minimize contamination from non-blazar sources. We considered constraints derived from the radio-optical spectral index and from the infrared and optical colors. We identified the variable objects through an optical variability analysis of Pan-STARRS light curves using two reference samples of stars. We further selected sources whose variability exceeds the level observed in quasars. This led to the selection of 3467 candidates with blazar-like properties and strong optical variability. Only 45% is available in other blazar candidate catalogs, with the remainder representing new identifications. In particular, we unveil a large population of faint sources, down to r~20.5. The blazar nature of a subsample of these sources is confirmed by available spectra. Our work offers new insights into the blazar population and serves as a foundation for future variability studies, especially in view of the upcoming Legacy Survey of Space and Time at the Vera C. Rubin Observatory, which will reach even fainter sources.
Author(s): Casadei S.; Raiteri C.M.; Carnerero M.I.; Capetti A.; Massaro F.
IVOA id: ivo://cds.vizier/j/a+a/708/a220

Taurus and Upper Sco brown dwarfs phot. and masses

2026-04-08T11:55:33Z

Description: Free-floating planetary mass objects -worlds that roam interstellar space untethered to a parent star-challenge conventional notions of planetary formation and migration, but also of star and brown dwarf formation. We focus on the multiplicity among free-floating planets. By virtue of their low binding energy (compared to other objects formed in these environments), these low-mass substellar binaries represent a most sensitive probe of the mechanisms at play during the star formation process. We use the Hubble Space Telescope and its Wide Field Camera 3 and the Very Large Telescope and its ERIS adaptive optics facility to search for visual companions among a sample of 77 objects members of the Upper Scorpius and Taurus young nearby associations with estimated masses in the range between approximately 6-66Mjup We report the discovery of one companion candidate around a Taurus member with a separation of 111.9+/-0.4mas, or ~18au assuming a distance of 160pc, with an estimated primary mass in the range between 3-6Mjup and a secondary mass between 2.6-5.2M_Jup_, depending on the assumed age. This corresponds to an overall binary fraction of 1.8^+2.6^_-1.3_% among low-mass brown dwarfs and free-floating planetary mass objects over the separation range >7au. Despite the limitations of small-number statistics and variations in spatial resolution and sensitivity, our results, combined with previous high-spatial-resolution surveys, suggest a notable difference in the multiplicity properties of objects below ~30-50Mjup between Upper Sco and Taurus. In Taurus, a binary fraction of 5.6^+3.2^_-2.3_% is found for objects with masses below 30Mjup, and of 7.8^+3.0^_-2.4_% for objects with masses below 50Mjup, whereas no binary were found among 80 objects over the matching luminosity range in Upper Sco, corresponding to an upper limit of >=1.2%. This difference may point to intrinsically distinct formation conditions, with warmer parental molecular clouds originally present in Upper Sco potentially inhibiting fragmentation into the lowest-mass brown dwarfs and free-floating planets compared to cooler environments such as Taurus.
Author(s): Bouy H.; Duchene G.; Strampelli G.; Aguilar J.; Olivares J.; Palau A.,Barrado D.; Raymond S.N.; Huelamo N.; Tamura M.; Bertin E.; Brandner W.,Cuillandre J.-C.; Galli P.A.B.; Miret-Roig N.
IVOA id: ivo://cds.vizier/j/a+a/708/a218

NGC 1487 MeerKAT image

2026-04-08T11:53:27Z

Description: Radio continuum observations of dwarf-dwarf galaxy mergers, such as NGC 1487, provide crucial insights into magnetic field amplification and cosmic ray (CR) propagation during galactic assembly. Dwarf galaxies are important laboratories for studying cosmic magnetism because they can maintain strong magnetic fields via the action of turbulent dynamo despite their low mass and weak gravitational potential. The Magnetic-field Evolution in Dwarf galaxies from Ultra-deep SKA Analysis (MEDUSA) survey is the first SKA-pathfinder programme designed to obtain deep continuum, polarisation, and HI data for dwarf galaxies, enabling a comprehensive study of their radio spectra, magnetic fields, and gas kinematics across a representative population By analysing the radio continuum spectra and polarisation of the dwarf-dwarf galaxy merger NGC 1487 from the MEDUSA sample, our aim was to determine its magnetic field strength and to characterise the large-scale and turbulent components of its magnetic field. We utilised highly sensitive multi-band radio continuum data from MeerKAT L-band (1.28GHz) and Australia Telescope Compact Array (ATCA) L/S (2.1GHz), C (5.5GHz), and X-bands (9GHz). We analysed the magnetic field configuration using polarisation and rotation measure (RM) synthesis. The integrated spectral energy distribution has a non-thermal spectral index of {alpha}nth=-0.678+/-0.085, indicating a significant synchrotron contribution, consistent with a CR electron injection index of gamma=2.36 (N(E){prop.to}E^-gamma^) typical of supernova remnants. Synchrotron and inverse Compton losses cause a spectral break at {nu}b=6.2+/-1.3GHz. In star-forming regions, the magnetic field exhibits strong small-scale fluctuations in RM, suggesting the action of a small-scale dynamo. Conversely, the field becomes more ordered, aligning with the tidal arms towards the galaxy's outskirts, showing a large-scale magnetic field over ~=3kpc. The CR cooling timescale of approximately 11Myr at 1.28GHz is similar to the escape timescale. Observations of the dwarf-dwarf merger NGC 1487 show that even low-mass galaxy mergers, likely the building blocks of larger galaxies in the early Universe, can rapidly amplify and produce coherent large-scale magnetic field structures, highlighting their contribution in the early magnetisation of galaxies.
Author(s): Taziaux S.; Basu A.; Das S.; Bomans D.; Galvin T.; Thomson A.; Heald G.,Kamphuis P.; Loi F.; Stein M.; Chyzy K.; Riseley C.; Dettmar R.-J.,Becker Tjus J.
IVOA id: ivo://cds.vizier/j/a+a/708/a212

S-PLUS Fornax Project (S+FP)

2026-04-08T11:52:14Z

Description: Observational extragalactic catalogs over wide sky areas are essential for uncovering the large-scale structure of the Universe. They allow, among others, cosmological studies and density analyses that impose strong constraints on models of galaxy formation and evolution. By taking advantage of the wide field images and the 12 optical bands of the Southern Photometric Local Universe Survey (S-PLUS), we aim at providing a catalog of galaxies located, in projection, towards the Fornax galaxy cluster, within ~5 virial radii in right ascension (R.A.) and ~ 3virial radius in declination (Dec) around NGC 1399, the dominant galaxy of the cluster. Such a catalog will allow unprecedented large-scale structure studies in that sky region. Supervised deep learning algorithms have been developed, utilizing neural networks complemented with dimensionality reduction techniques, to classify and separate spurious objects, stars and galaxies in a photometric catalog previously built for the S-PLUS Fornax Project (S+FP). That catalog was built using a combination of SExtractor configurations optimized for galaxy detection and characterization. A catalog of 119580 galaxies was obtained in the direction of the Fornax cluster containing photometric information in the 12 optical bands of S-PLUS complemented with GALEX (UV), VHS-VISTA (NIR) and AllWISE (MIR) data. We estimate photometric redshifts ({sigma}_NMAD_~0.0219) with a lower limit of zlim~0.03. Stellar masses, star formation rates (SFRs) and D4000N index estimates were obtained through a machine learning approach, by matching S-PLUS photometric data to SDSS spectroscopic data. The completeness of the catalog (72%) was calculated by comparing with mock catalogs. Taking into account our zlim, we were able to identify 119230 background galaxies and to find 350 candidates to be Fornax members or infalling galaxies, not included in our compilation of 1005 galaxies previously reported in the literature. We were also able to classify the galaxies in our catalog as quiescent (43%), star-forming (39%) and transition (18%) galaxies. In addition, 181 emission line galaxy (ELG) candidates were identified using the filter J0660. The spatial distribution of the galaxies in our catalog show projected overdensities that match 89 background clusters identified by eROSITA. This confirms the robustness of our catalog in tracing real structures. In that context, we expect that the extragalactic catalog of the S+FP allows us to better understand the large-scale structure in the direction of the Fornax cluster, and to identify the substructures that are feeding Fornax.
Author(s): Haack R.F.; Smith Castelli A.V.; Sodre L. Jr; Mendes de Oliveira C.,Lopes A.R.; Gutierrez-Soto L.A.; Demarco R.; Olave-Rojas D.E.,Carrasco E.R.; Humire P.K.; Calderon J.P.; de Almeida Fernandes F.,Lomeli-Nunez L.; Sepulveda G.; Lima-Dias C.; Torres Flores S.; Telles E.,Cardoso N.M.; Palma D.; Doubrawa L.; Pallero D.; Marinello M.; Schoenell W.,Ribeiro T.; Kanaan A.
IVOA id: ivo://cds.vizier/j/a+a/708/a204

Formaldehyde observations

2026-04-08T11:43:42Z

Description: Measurements of the physical conditions in molecular clumps are key to our understanding of star formation. Formaldehyde (H_2_CO) is a molecule prevalent in these regions that can be used as diagnostic for the physical conditions in them. Here we explore a technique for determining the volume density and gas kinetic temperature in molecular clumps across various evolutionary phases and environments. The ground-state transition of H_2_CO has a critical density of n_crit_~10^4^cm^-3^, allowing us to use this molecule as a densitometer at n<=10^5^cm^-3^ and lessen the discrepancy between the measurements between gas densities derived from molecular tracers and those derived of dust observations. The clumps have been observed with the IRAM 30-m telescope, marking the first extensive survey of the H_2_CO (1_0,1_-0_0,0_) line across a large sample of sources. These observations were complemented by the H_2_CO J=3-2 lines, obtained using the APEX telescope. These clumps have been surveyed in three regions, the Cygnus-X giant molecular cloud complex, the GLOSTAR pilot region covering the Galactic plane at longitudes 28{deg}<=l<=36{deg}, and the molecular cloud associated with the HII regions in the Lagoon nebula (M8). We analyzed a total of 127 clumps, including 78 from Cygnus-X, 12 from the GLOSTAR pilot region, and 37 from M8. We derived the gas kinetic temperature, volume densities and H_2_CO column densities using radiative transfer modeling with pyradex+emcee in 102 clumps. We reproduce the observed line intensities in the sources with volume densities n(H_2_)=5.4x10^4^-3.8x10^5^cm^-3^, gas kinetic temperatures Tgas=16-219K, and H_2_CO column densities N(H_2_CO)=6.0x10^12^-1.6x10^15^cm^-2^. The gas kinetic temperatures obtained from the non-LTE modeling with pyradex+emcee agree well with the LTE gas kinetic temperature obtained from the ratio of H_2_CO (3_0,3_-2_0,2_) and H_2_CO (3_2,1_-2_2,0_) lines at densities n(H_2_)<=10^5.5^cm^-3^. However, we find that, at higher densities, LTE temperatures derived from this ratio are overestimated by up to 0.5dex. The measured volume densities are consistent with the volume densities obtained from dust continuum measurements, thereby probing the bulk of the gas. Furthermore, we find that the volume densities and dust temperatures increase, with increasing evolutionary phase. The newly available ground-state transition of H_2_CO allows to constrain the physical conditions in various phases of star formation more effectively.
Author(s): Barlach Christensen I.; Gieser C.; Wyrowski F.; Nguyen H.; Hoang T.D.,Veena V.S.; Beuther H.; Kahle K.A.; Gong Y.; Menten K.M.
IVOA id: ivo://cds.vizier/j/a+a/708/a201

Ultraviolet spectroscopy of MWC 656

2026-04-08T11:41:58Z

Description: The Galactic Be star binary MWC 656 was long considered the only known Be star +black hole (BH) system, making it a critical benchmark for models of massive binary evolution and for the expected X-ray emission of Be+BH binaries. However, recent dynamical measurements cast doubt on the presence of a BH companion. We present new multi-epoch ultraviolet spectroscopy from the Hubble Space Telescope, combined with high-resolution optical spectra, to reassess the nature of the companion. The far-ultraviolet spectra reveal high-ionisation features -- including prominent NV and HeII lines -- which are absent in the spectra of normal Be stars and are indicative of a hot, luminous companion. Spectral modelling shows that these features cannot originate from the Be star or from an accretion disc around a compact object. Instead, we find that the data are best explained by a hot (T_eff_~85kK), compact, hydrogen-deficient star with strong wind signatures, consistent with an intermediate-mass stripped star. Our revised orbital solution and composite spectroscopic modelling yield a companion mass of M_2_=1.48^+0.55^_-0.46_M_{sun}_, definitively ruling out a BH and disfavouring a white dwarf. MWC 656 thus joins the growing class of Be+stripped star binaries. The system's unusual properties -- including a high companion temperature and wind strength -- extend the known parameter space of such binaries. The continued absence of confirmed OBe+BH binaries in the Galaxy highlights a growing tension with population synthesis models.
Author(s): Mueller-Horn J.; Ramachandran V.; El-Badry K.; Sander A.A.C.,Bodensteiner J.; Gies D.R.; Goetberg Y.; Rivinius T.; Shenar T.,Schoesser E.C.; Wang L.; Bieryla A.; Buchhave L.A.; Latham D.W.
IVOA id: ivo://cds.vizier/j/a+a/708/a187

Stellar and planetary param. of M-dwarf systems

2026-04-07T10:34:12Z

Description: Planetary radii are derived for 218 exoplanets orbiting 161 M dwarf stars. Stellar radii are based on an analysis of APOGEE high-resolution near-IR spectra for a subsample of the M dwarfs; these results are used to define a stellar radius-M_Ks_ calibration that is applied to the sample of M-dwarf planet hosts. The planetary radius distribution displays a gap over Rp~1.6-2.0R_{Earth}_, bordered by two peaks at Rp~1.2-1.6R_{Earth}_ (super-Earths) and 2.0-2.4R_{Earth}_ (sub-Neptunes). The radius gap is nearly constant with exoplanetary orbital period (a power-law slope of m=+0.01_-0.04_^+0.03^), which is different (2{sigma}-3{sigma}) from m~-0.10 found previously for FGK dwarfs. This flat slope agrees with pebble accretion models, which include photoevaporation and inward orbital migration. The radius gap as a function of insolation is approximately constant over the range of Sp~20-250S_{Earth}_. The Rp-Porb plane exhibits a sub-Neptune desert for Porb<2-days, which appears at Sp>120S_{Earth}_, being significantly smaller than Sp>650S_{Earth}_ found in the FGK planet-hosts, indicating that the appearance of the sub-Neptune desert is a function of host- star mass. Published masses for 51 exoplanets are combined with our radii to determine densities, which exhibit a gap at {rho}_p_~0.9{rho}_{Earth}_, separating rocky exoplanets from sub-Neptunes. The density distribution within the sub-Neptune family itself reveals two peaks, at {rho}_p_~0.4{rho}_{Earth}_ and ~0.7{rho}_{Earth}_. Comparisons to planetary models find that the low-density group are gas-rich sub-Neptunes, while the group at <{rho}_p_>~0.7{rho}_{Earth}_ likely consists of volatile-rich water worlds.
Author(s): Wanderley F.; Cunha K.; Smith V.V.; Souto D.; Pascucci I.; Behmard A.,Allende Prieto C.; Beaton R.L.; Bizyaev D.; Daflon S.; Hasselquist S.,Howell S.; Majewski S.R.; Pinsonneault M.
IVOA id: ivo://cds.vizier/j/apj/993/233

Relative magnetic fields of 3 M dwarfs

2026-04-06T12:55:08Z

Description: Setting observational constraints on stellar magnetic fields is essential for both stellar and planetary physics. They play a key role in the formation and evolution of stars and planets, and they are responsible for spurious signals in radial velocity curves that impact the detection and characterization of exoplanets. Recent observations have revealed the diversity and evolution of large-scale magnetic fields in low-mass stars. However, these large-scale fields only account for a small fraction of the observed unsigned magnetic flux. The other crucial stellar magnetism information originates from (spatially) small-scale magnetic fields, which account for most of the surface magnetic flux and exhibit a clear temporal evolution on timescales of many years. With this work, we aim to develop new fast techniques to extract small-scale magnetic field estimates from time series of observed high-resolution spectra. One objective is to develop tools that will enable the community to take full advantage of the upcoming monitoring surveys carried out with various high-resolution spectrometers. Our ultimate goal is to study the temporal evolution of small-scale magnetic fields and offer insights into the magnetic properties of low-mass stars and their magnetic cycles. We implemented a process to capture relative pixel variations caused by changes in magnetic field strengths, relying on synthetic spectra computed with ZeeTurbo. This approach provides extremely fast and reliable estimates of relative magnetic field strength variations from series of high-resolution spectra, mitigating the impact of systematics between models and observations. We assessed the performance of the proposed method through its application to simulated data and publicly available observed spectra recorded with SPIRou, Narval, and ESPaDOnS. In addition, we implemented a model-driven process to derive relative temperature variations and we explored the influence magnetic fields have on these measurements. Our results are in excellent agreement with the magnetic field estimates previously obtained from spectra recorded with SPIRou. This method provides robust constraints on the structure of the magnetic field variations and proves to be relatively insensitive to small changes in the assumed atmospheric parameters and broadening. We find that magnetic field variations have the potential of introducing biases in relative temperature estimates. This is particularly relevant in the case of the Narval/ESPaDOnS spectral domains, which contain a large number of magnetically sensitive transitions and where contrast is more important. Our application to archival data provides new constraints on the evolution of small-scale magnetic fields and underscores the potential of the proposed method for analyzing data in the context of large observation programs. By reducing the problem to a set of linear equations, our method offers extremely fast results, making it viable for integration in future pipelines developed for large spectroscopic surveys. These estimates will provide much needed information to correct radial velocity curves and constrain dynamo processes.
Author(s): Cristofari P.I.; Saar S.H.; Vidotto A.A.; Bellotti S.
IVOA id: ivo://cds.vizier/j/a+a/709/a207