VO Fresh

AMS-02 All Particle Rates Catalog

2026-10-16T00:00:00Z

Description: The AMS02RATES database table records the incident rates for all particle species obtained with the Alpha Magnetic Spectrometer (AMS-02) experiment on the International Space Station (ISS), a cosmic ray particle detector installed in May 2011. The experiment consists of several components, which collectively measure particle species, energy, geomagnetic rigidity, or veto off-axis particles and high-energy photons. The experiment covers the energy range of ~0.1 GeV - ~2 TeV. AMS-02 is the result of a collaboration between MIT, the University of Hawaii, CERN, NASA, the U.S. Department of Energy, and ESA. It was launched on the Space Shuttle Endeavor (STS-134) on May 16, 2011 and was installed three days later at which time science operations commenced. Operations were interrupted by in-flight servicing of the cooling pumps for the silicon tracker: servicing took place between November 2019 and January 2020, after which science operations were restored. It is anticipated to continue operations for as long as the ISS itself remains functional. The rate at which all particle species are observed within a one-second time integration period is recorded for each interval, corrected for the livetime fraction. Each integration period contains the livetime value, observed rate, and the position of the AMS-02 instrument in latitude, longitude, and radius from the Earth's center in the Earth Centered Earth Fixed (ECEF) frame of reference. This database table was first ingested by the HEASARC in July 2026. The AMS-02 team in collaboration with the HEASARC developed the FITS file structure for these data which were created by the HEASARC from daily particle rate data provided by the AMS collaboration. The data and the database table are updated periodically to reflect additional data as they become available. This is a service provided by NASA HEASARC .
Author(s): HEASARC
IVOA id: ivo://nasa.heasarc/ams02rates

AMS-02 Spectral Results Catalog

2026-10-16T00:00:00Z

Description: The AMS02SPEC database table records the spectral results obtained with the Alpha Magnetic Spectrometer (AMS-02) experiment on the International Space Station (ISS), a cosmic ray particle detector installed in May 2011. The experiment consists of several components, which collectively measure particle species, energy, geomagnetic rigidity, or veto off-axis particles and high-energy photons. The experiment covers the energy range of ~0.1 GeV - ~2 TeV. AMS-02 is the result of a collaboration between MIT, the University of Hawaii, CERN, NASA, the U.S. Department of Energy, and ESA. It was launched on the Space Shuttle Endeavor (STS-134) on May 16, 2011 and was installed three days later at which time science operations commenced. Operations were interrupted by in-flight servicing of the cooling pumps for the silicon tracker: servicing took place between November 2019 and January 2020, after which science operations were restored. It is anticipated to continue operations for as long as the ISS itself remains functional. This database table was first ingested by the HEASARC in June 2026. The AMS-02 team in collaboration with the HEASARC developed the FITS file structure for these data. The data have been published in a series of papers (see bibliographic references) and archived in FITS format at the HEASARC. The data and the database table are updated periodically to reflect additional data as they becomes available. This is a service provided by NASA HEASARC .
Author(s): HEASARC
IVOA id: ivo://nasa.heasarc/ams02spec

Chandra Source Catalog Stacked Observation Detections, v2.1.1

2026-10-16T00:00:00Z

Description: The Chandra Source Catalog's Stacked Observation Detections Table (CSCSTACK) includes 493,236 detections (855,402 total entries consisting of detections plus photometric upper limits) based on 10,034 stacks of X-ray observations. Exploiting the unique resolution and very low background of Chandra data, the limiting sensitivity of the catalog is enhanced significantly by stacking (co-adding) multiple observations of the same field prior to source detection. To minimize the impact of the variation in the Chandra point spread function (PSF) with off-axis angles, source detection is constrained to run on stacks of observations that have telescope pointings that are co-located within 60 arcseconds and that were obtained using the same instrument (ACIS or HRC-I). Formally, the observations are matched using a tree clustering algorithm with complete linkage. This means that the pointing direction of every observation in the stack is co-aligned with the pointing direction of every other observation in the stack within 60 arcseconds. The stacked-observation level allows composite properties to be reported from the co-added observations for detections that would otherwise not be visible or have poor S/N in individual observations, while for higher S/N detections the per-observation properties facilitate analysis of variable sources. CSCSTACK is related to the <a href="/W3Browse/chandra/csc.html">Chandra Source Catalog (CSC)</a> catalog, which is the definitive catalog of X-ray sources detected by the Chandra X-ray Observatory. The CSC contains 407,806 unique compact and extended X-ray sources. By combining Chandra's sub-arcsecond on-axis spatial resolution and low instrumental background with consistent data processing, the CSC delivers a wide variety of uniformly calibrated properties and science ready data products for detected sources over four decades of flux. Each identified distinct X-ray source on the sky is represented in the catalog by one or more "stack detection" entries -- one for each stack in which the source has been detected -- and a single "master source" entry. The individual stack entries record all of the properties about a detection extracted from a single stack, as well as associated file-based data products, which are stack-specific. If a source is detected in one or more stacked-observations, photometric upper limits that are useful for temporal variability analyses are calculated for any overlapping stacked- and individual-observations in which the source is not detected. This database table was ingested by the HEASARC in July 2026 and is based on a download of the online version of the "Stacked Observation Detections" Table v. 2.1.1, at the CXC using the CLI. Refer to <a href="https://cxc.harvard.edu/csc/cli/">https://cxc.harvard.edu/csc/cli/</a> for details. This is a service provided by NASA HEASARC .
Author(s): Evans, Civano
IVOA id: ivo://nasa.heasarc/cscstack

Swift-XRT Living Point Source Catalog (LSXPS)

2026-10-16T00:00:00Z

Description: This is the Live Swift X-ray Point Source (LSXPS) catalog of detections by the Swift X-ray Telescope (XRT) used in Photon Counting (PC) mode in the 0.3-10 keV energy range. Swift is a NASA mission with international participation dedicated to studying gamma-ray bursts. It carries three instruments. The BAT is the large field-of-view instrument and operates in the 10-300 keV energy band; and two narrow field instruments, XRT and UVOT, that operate in the X-ray and UV/optical regime, respectively. This catalog is similar to the <a href="swift2sxps.html">2SXPS</a> catalog (Evans, P. A., et al. 2020, ApJS, 247, 54) and uses an almost identical source detection process. The primary change is that this is a living catalog: it is updated in near-real time and transient searches are carried out on each dataset as it is received. The improved statistics (below) compared to 2SXPS for source detections, unique and variables sources, uncatalogued sources, and temporal and total sky area coverage are a function of its ongoing live nature, compared to the static 2SXPS which was current up to 2018-08-01. On average, LSXPS grows by 49 new sources and the unique sky coverage increases 0.94 square degrees per day. This table was added to the HEASARC database in June 2026 and is based on the contents of its dedicated website at <a href="https://www.swift.ac.uk/LSXPS">https://www.swift.ac.uk/LSXPS</a>. The version available from the HEASARC corresponds to the catalog designated as "Sources" on the Leicester website and will typically be updated at the HEASARC within a day or so of a new version appearing on the Leicester website. This is a service provided by NASA HEASARC .
Author(s): Evans et al.
IVOA id: ivo://nasa.heasarc/swiftlsxps

LAMOST DR12 V2.0 TAP Service

2026-10-15T12:26:05Z

Description: LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) DR12 Table Access Protocol (TAP) service. TAP lets you execute ADQL queries against LAMOST database tables, inspect metadata, and retrieve catalog and spectrum data. This is the IVOA standard interface for accessing LAMOST DR12 data products.
Author(s): The LAMOST Team
IVOA id: ivo://purx/lamost/dr12/v2.0/tap

LAMOST DR11 V2.0 TAP Service

2026-10-15T12:26:05Z

Description: LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) DR11 Table Access Protocol (TAP) service. TAP lets you execute ADQL queries against LAMOST database tables, inspect metadata, and retrieve catalog and spectrum data. This is the IVOA standard interface for accessing LAMOST DR11 data products.
Author(s): The LAMOST Team
IVOA id: ivo://purx/lamost/dr11/v2.0/tap

LAMOST DR10 V2.0 TAP Service

2026-10-15T12:26:05Z

Description: LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) DR10 Table Access Protocol (TAP) service. TAP lets you execute ADQL queries against LAMOST database tables, inspect metadata, and retrieve catalog and spectrum data. This is the IVOA standard interface for accessing LAMOST DR10 data products.
Author(s): The LAMOST Team
IVOA id: ivo://purx/lamost/dr10/v2.0/tap

LAMOST DR8 V2.0 Low Resolution Catalog Simple Cone Search

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 8 publish 10,633,515 Low Resolution spectrum and objects
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr8/v2.0/lrs/conesearch

LAMOST DR12 Medium Resolution Simple Spectrum Access Service

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 12 publish 15,471,446 Medium Resolution spectrum and objects, this catalog contain all the 56,291,670 entries in the catalog while 1 obsid might have multiple entries.
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr12/v2.0/mrs/ssa

LAMOST DR12 V2.0 Medium Resolution Catalog Simple Cone Search

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 12 publish 15,471,446 Medium Resolution spectrum and objects, this catalog contain all the 56,291,670 entries in the catalog while 1 obsid might have multiple entries
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr12/v2.0/mrs/conesearch

LAMOST DR12 Low Resolution Simple Spectrum Access Service

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 12 publish 12,602,862 Low Resolution spectrum and objects
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr12/v2.0/lrs/ssa

LAMOST DR12 V2.0 Low Resolution Catalog Simple Cone Search

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 12 publish 12,602,862 Low Resolution spectrum and objects
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr12/v2.0/lrs/conesearch

LAMOST DR11 Medium Resolution Simple Spectrum Access Service

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 11 publish 13,156,050 Medium Resolution spectrum and objects, this catalog contain all the 46,953,010 entries in the catalog while 1 obsid might have multiple entries.
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr11/v2.0/mrs/ssa

LAMOST DR11 V2.0 Medium Resolution Catalog Simple Cone Search

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 11 publish 13,156,050 Medium Resolution spectrum and objects, this catalog contain all the 46,953,010 entries in the catalog while 1 obsid might have multiple entries
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr11/v2.0/mrs/conesearch

LAMOST DR11 Low Resolution Simple Spectrum Access Service

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 11 publish 11,931,197 Low Resolution spectrum and objects
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr11/v2.0/lrs/ssa

LAMOST DR11 V2.0 Low Resolution Catalog Simple Cone Search

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 11 publish 11,931,197 Low Resolution spectrum and objects
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr11/v2.0/lrs/conesearch

LAMOST DR10 V2.0 Medium Resolution Catalog Simple Cone Search

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 10 publish 11,029,844 Medium Resolution spectrum and objects, this catalog contain all the 39,376,269 entries in the catalog while 1 obsid might have multiple entries
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr10/v2.0/mrs/conesearch

LAMOST DR10 Low Resolution Simple Spectrum Access Service

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 10 publish 11,441,011 Low Resolution spectrum and objects
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr10/v2.0/lrs/ssa

LAMOST DR10 V2.0 Low Resolution Catalog Simple Cone Search

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 10 publish 11,441,011 Low Resolution spectrum and objects
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr10/v2.0/lrs/conesearch

LAMOST DR9 Medium Resolution Simple Spectrum Access Service

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 9 publish 8,640,783 Medium Resolution spectrum and objects, this catalog contain all the 31,304,690 entries in the catalog while 1 obsid might have multiple entries.
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr9/v2.0/mrs/ssa

LAMOST DR10 Medium Resolution Simple Spectrum Access Service

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 10 publish 11,029,844 Medium Resolution spectrum and objects, this catalog contain all the 39,376,269 entries in the catalog while 1 obsid might have multiple entries.
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr10/v2.0/mrs/ssa

LAMOST DR8 Medium Resolution Simple Spectrum Access Service

2026-10-14T16:32:10Z

Description: The LAMOST Spectroscopic Survey Data Release 8 publish 5,975,982 Medium Resolution spectrum and objects, this catalog contain all the 22,141,635 entries in the catalog while 1 obsid might have multiple entries.
Author(s): The LAMOST Team
IVOA id: ivo://purx/service/lamost/dr8/v2.0/mrs/ssa

Extended Orion Nebula HI 21cm emission maps

2026-10-10T20:03:50Z

Description: The Orion nebula is the nearest site of ongoing and recent high-mass star formation. It is a unique laboratory for studying the mass, energy, and momentum input from high-mass stars. We present 21-centimeter emission line observations that resolve for the first time the neutral atomic hydrogen (HI) gas in the extended Orion nebula (EON) at a resolution of one arcminute, which corresponds to a physical scale of 0.12 parsecs at the standard distance to the region. Our HI emission maps reveal an expanding shell that matches the EON contours delineated by recent observations of ionized carbon ([CII]) line emission. However, our combination of single-dish and interferometric HI observations suggests 100 solar masses of material for the front hemisphere of the shell, which is lower by roughly a factor of ten than the mass inferred from [CII] observations. This discrepancy suggests that the mass of the nearest wind-blown bubble has been overestimated, although we do not rule out the possibility that a significant amount of molecular hydrogen (H_2_) in the shell may account for part of the difference. Our extended 21cm line maps also reveal uncharted structures in and around the EON. They include a probable secondary bubble and a linear protrusion extending roughly four parsecs from the shell boundary. Our results illustrate the potential of HI interferometric observations to elucidate key aspects of the multiphase structure of star-forming regions and their connection to their surroundings.
Author(s): Soler J.D.; Beuther H.; Glover S.C.O.; Klessen R.S.; Ott J.; Rugel M.,Teh J.W.; Clark S.E.; Goldsmith P.; Hacar A.; Socci A.; Heyer M.; Lee M.-Y.,Murray C.E.; Seifried D.; Walch S.; Godard B.; Miville-Deschenes M.-A.
IVOA id: ivo://cds.vizier/j/a+a/711/a85

Magnetic delta Scuti candidates

2026-10-10T20:03:48Z

Description: delta Scuti stars are pulsating stars constituting the delta Scuti instability strip in the Hertzsprung-Russell (HR) diagram, which consists of A and F stars of various evolutionary stages. They are in the transition region between high-mass hot stars and low-mass solar-like stars, making understanding their magnetic properties essential to painting a complete picture of magnetism across the HR diagram. Furthermore, discovering magnetic delta Scuti stars allows for magneto-asteroseismology, which can be used to determine the internal rotation profile, internal magnetic field strength, and the efficiency of mixing and transport processes more accurately than classical asteroseismology. To date, magnetic fields have been detected at the surface of 13 delta Scuti stars. However, the overall incidence rate of magnetism in these stars remains unknown. Fossil magnetic fields are detected in 10% of OBA stars. The goal of this work is to find out if it is the same for delta Scuti stars. We investigated the incidence rate of surface magnetic fields among delta Scuti stars using photometric data from the CoRoT space mission. We analyzed long-duration (~5 months) light curves of ~1750 delta Scuti stars to search for pulsations and rotational modulation - a photometric signature that indicates chemical or temperature spots at the stellar surface, usually caused by magnetic fields. We identified 147 rotational variables that we designate as magnetic candidates, thus potentially increasing the known population of magnetic delta Scuti stars drastically and suggesting an incidence rate of fossil magnetic fields in delta Scuti stars similar to the incidence rate in OBA stars in general. Our analysis also revealed a few delta Scuti-gamma Dor hybrid stars and four binary stars in the sample. We determined the rotation periods and projected rotation velocities of the magnetic candidates in order to select suitable targets for follow-up spectropolarimetric observations aimed at confirming and characterizing their magnetic fields.
Author(s): Paul G.; Neiner C.; Catala C.; Labadie-Bartz J.
IVOA id: ivo://cds.vizier/j/a+a/711/a128

LK-MRS Phase II. 5 year obs. from LAMOST DR11

2026-10-09T20:23:19Z

Description: The LAMOST-Kepler/K2 Medium-Resolution Spectroscopic Survey (LK-MRS) conducted time-domain (TD) medium-resolution spectroscopic observations of 20 LAMOST plates in the Kepler and K2 fields from 2018 to 2023, a phase designated as LK-MRS-I. A catalog of stellar parameters for a total of 36,588 stars, derived from the spectra collected during these 5yr, including the effective temperature, the surface gravity, the metallicity, the {alpha}-element abundance, the radial velocity (RV), and vsini of the target stars, is released, together with the weighted averages and uncertainties. At a signal-to-noise ratio = 10, the measurement uncertainties are 120K, 0.18dex, 0.13dex, 0.08dex, 1.9km/s, and 4.0km/s for the above parameters, respectively. Comparisons with the parameters provided by the APOGEE and GALAH surveys validate the effective temperature and surface gravity measurements, showing minor discrepancies in metallicity and {alpha}-element abundance values. We identified some peculiar star candidates, including 764 metal-poor stars, 174 very metal-poor stars, and 30 high-velocity stars. Moreover, we found 2333 stars whose RV seems to be variable. Using Kepler/K2 or TESS photometric data, we confirmed 371 periodic variable stars among the RV variable candidates and classified their variability types. LK-MRS-I provides spectroscopic data that is useful for studies of the Kepler and K2 fields. The LK-MRS project will continue collecting TD medium-resolution spectra for target stars during the third phase of LAMOST surveys, providing data to support further scientific research.
Author(s): Qin M.; Fu J.-N.; Zong W.; De Cat P.; Frasca A.; Cang T.; Wang J.; Shi J.,Luo A.; Zhang H.; Yan H.; Molenda-Zakowicz J.; Gray R.O.; Wang J.
IVOA id: ivo://cds.vizier/j/apjs/280/19

HST archival & new obs. of Miras in M101

2026-10-09T20:20:52Z

Description: The giant spiral galaxy M101 is host to the nearest recent Type Ia supernova (SN 2011fe) and thus has been extensively monitored in the near-infrared to study the late-time light curve of the SN. Leveraging this existing baseline of observations, we derive the first Mira-based distance to M101 by discovering and classifying a sample of 211 Miras with periods ranging from 240-400 days in the SN field. Combined with new Hubble Space Telescope (HST) WFC3/IR channel observations, our data set totals 11 epochs of F110W (HST YJ) and 13 epochs of F160W (HST H) data spanning ~2900 days. We adopt absolute calibrations of the Mira period-luminosity relation based on geometric distances to the Large Magellanic Cloud and the water megamaser host galaxy NGC 4258, and find {mu}_M101_=29.10{\pm}0.06mag. This distance is in 1{sigma} agreement with most other recent Cepheid and tip of the red giant branch distance measurements to M101. Including the previous Mira SN Ia host, NGC 1559, and SN 2005df, we determine the fiducial SN Ia peak luminosity, M_B_^0^=-19.27+/-0.09mag. With the Hubble diagram of supernovae Ia, we derive H_0_=72.37{\pm}2.97km/s/Mpc, a 4.1% measurement of H0 using Miras. We find excellent agreement with recent Cepheid distance ladder measurements of H0 and confirm previous indications that the local universe value of H0 is higher than the early universe value at ~95% confidence. Currently, the Mira-based H0 measurement is still dominated by the statistical uncertainty in the SN Ia peak magnitude.
Author(s): Huang C.D.; Yuan W.; Riess A.G.; Hack W.; Whitelock P.A.; Zakamska N.L.,Casertano S.; Macri L.M.; Marengo M.; Menzies J.W.; Smith R.K.
IVOA id: ivo://cds.vizier/j/apj/963/83

Virial factor in SDSS AGNs from supermassive BH masses

2026-10-09T20:20:51Z

Description: Under the hypothesis of gravitational redshift induced by the central supermassive black hole and based on line widths and shifts of redward-shifted H{beta} and H{alpha} broad emission lines for more than 8000 Sloan Digital Sky Survey DR7 active galactic nuclei (AGNs), we measure the virial factor in determining supermassive black hole masses. The virial factor had been believed to be independent of accretion radiation pressure on gas clouds in broad-line regions (BLRs) and only dependent on the inclination effects of BLRs. The virial factor measured spans a very large range. For the vast majority of AGNs (>96%) in our samples, the virial factor is larger than the f=1 usually used in the literature. The f-correction makes the percent of high-accreting AGNs decrease by about 100 times. There are positive correlations of f with the dimensionless accretion rate and Eddington ratio. The redward shifts of H{beta} and H{alpha} are mainly of gravitational origin, confirmed by a negative correlation between the redward shift and the dimensionless radius of the BLR. Our results show that radiation pressure force is a significant contributor to the measured virial factor, containing the inclination effects of the BLR. The usually used values of f should be corrected for high-accreting AGNs, especially high-redshift quasars. The f-correction increases their masses by 1-2 orders of magnitude, which will make it more challenging to explain the formation and growth of supermassive black holes at high redshifts.
Author(s): Liu H.T.; Feng H.-C.; Li S.-S.; Bai J.M.; Li H.Z.
IVOA id: ivo://cds.vizier/j/apj/963/30

Classifying intermediate-z galaxies in SDSS

2026-10-09T20:20:44Z

Description: We select a sample of 1437 active galactic nuclei (AGN) from the catalog of the Sloan Digital Sky Survey galaxy properties from the Portsmouth group by detection of the high-ionization [NeV]3426{AA} emission line. We compare the fluxes of [NeIII]3869{AA}, [OIII]5007{AA}, [OII]3726,3728{AA}, and [OI]6300{AA} to that of [NeV]. All four lines show a strong linear correlation with [NeV], although lines from ions with lower ionization potentials have a lower correlation coefficient. We investigate the use of two forbidden line ratio diagnostic diagrams that do not rely on H{alpha} in order to classify high-redshift galaxies. These use the [NeIII]/[OII] line ratio plotted against [OIII]/[OI] and [OIII]/[OII], respectively. We use photoionization modeling to characterize the behavior of the narrow-line region in AGN and star-forming regions and test the validity of our diagnostic diagrams. We also use a luminosity cutoff of logL[OIII][erg/s]=42, which lowers the contamination of the AGN region by star-forming galaxies down to 10% but does not remove green pea and purple grape galaxies from the AGN region. We also investigate the OHNO diagram, which uses [NeIII]/[OII] plotted against [OIII]/H{beta}. Using our new diagnostic diagrams, we are able to reliably classify AGN up to a redshift of z<=1.06 and add more than 822 new AGN to the [NeV]-selected AGN sample.
Author(s): Feuillet L.M.; Melendez M.; Kraemer S.; Schmitt H.R.; Fischer T.C.,Reeves J.N.
IVOA id: ivo://cds.vizier/j/apj/962/104

Hot subdwarf B stars periodic properties from ZTF

2026-10-09T16:12:46Z

Description: We conduct a systematic search for periodic variables in the hot subdwarf catalogue using data from the Zwicky Transient Facility. We present the classification of 67 HW Vir binaries, 496 reflection effect, pulsation or rotation sinusoids, 11 eclipsing signals, and 4 ellipsoidally modulated binaries. Of these, 486 are new discoveries that have not been previously published including a new mass-transferring hot subdwarf binary candidate. These sources were determined by applying the Lomb-Scargle and box least squares periodograms along with manual inspection. We calculated variability statistics on all periodic sources, and compared our results to traditional methods of determining astrophysical variability. We find that =~60 per cent of variable targets, mostly sinusoidal variability, would have been missed using a traditional varindex cut. Most HW Virs, eclipsing systems, and all ellipsoidal variables were recovered with a varindex >0.02. We also find a significant reddening effect, with some variable hot subdwarfs meshing with the main-sequence stripe in the Hertzsprung-Russell diagram. Examining the positions of the variable stars in Galactic coordinates, we discover a higher proportion of variable stars within |b| < 25{deg} of the Galactic plane, suggesting that the Galactic plane may be fertile grounds for future discoveries if photometric surveys can effectively process the clustered field.
Author(s): Wang K.; Kupfer T.; Barlow B.N.
IVOA id: ivo://cds.vizier/j/mnras/524/3769

NGC 4261 GCs/non-GCs ULXs, X-ray binaries/sources

2026-10-09T15:40:40Z

Description: Utilizing archival Chandra X-ray Observatory data and Hubble Space Telescope globular cluster catalogues, we probe the time-domain properties of the low mass X-ray binary population in the elliptical galaxy NGC 4261. Of the 98 unique X-ray sources identified in this study, 62 sources are within the optical field of view and, of those, 33 per cent are aligned with an optical cluster counterpart. We find twenty X-ray sources coincident with globular clusters; two are previously discovered ultra-luminous X-ray sources (ULXs) and eighteen are low mass X-ray binaries (GCLMXBs) with L_X_ < 10^39^ erg/s. ULXs are a heterogeneous class of extremely bright X-ray binaries (LX > 10^39^ erg/s) and ULXs located in globular clusters (GCULXs) and may be indicators of black holes. Identifying these unusually X-ray bright sources and measuring their optical properties can provide valuable constraints on the progenitors of gravitational wave sources. We compare observations of these sources to the twenty previously studied GCULXs from five other early-type galaxies, and find that GCULXs in NGC 4261 are of similar colour and luminosity and do not significantly deviate from the rest of the sample in terms of distance from the galaxy centre or X-ray luminosity. Both the GCULX and GCLMXB populations of NGC 4261 show long-term variability; the former may have implications for fast radio bursts originating in globular clusters and the latter will likely introduce additional scatter into the low mass end of GCLMXB X-ray luminosity functions.
Author(s): Nair S.; Dage K.C.; Haggard D.; Kundu A.; Plotkin R.M.; Rhode K.L.,Zepf S.E.
IVOA id: ivo://cds.vizier/j/mnras/524/3662

MAGG V C IV tracers and high-z LAEs galaxies

2026-10-09T15:19:46Z

Description: We study the connection between Ly{alpha} emitters (LAEs) and metal-enriched ionized gas traced by C IV absorption at redshift z =~ 3-4 in 28 quasar fields with high-resolution spectroscopy from the MUSE Analysis of Gas Around Galaxies survey. In a sample of 220 C IV absorbers, we identify 143 LAEs connected to C IV gas within a line-of-sight separation +/-500km.s^-1^, equal to a detection rate of 36 +/- 5 per cent once we account for multiple LAEs connected to the same absorber. The luminosity function of LAEs associated with absorbers has an =~2.4 higher normalization than the field. The analysis of the LAE-C IV correlation function suggests that metal-enriched gas arises both in the haloes of the LAEs and from locations not connected to galaxies. C IV absorbers with higher equivalent width are more often associated with LAEs and C IV systems are twice less likely, especially at low equivalent width, to be found near LAEs than strong H I absorbers. The covering fraction in groups is up to =~3 times larger than for isolated galaxies. Similar results are found using Si IV as tracer of ionized gas. We propose three components to model the gas environment of LAEs: (i) the circumgalactic medium of galaxies, accounting for the strongest correlations between absorption and emission; (ii) overdense gas filaments connecting galaxies, driving the excess of LAEs at a few times the virial radius and the modulation of the luminosity and cross-correlation functions for strong absorbers; (iii) an enriched and more diffuse medium, accounting for weaker C IV absorbers farther from galaxies.
Author(s): Galbiati M.; Fumagalli M.; Fossati M.; Lofthouse E.K.; Dutta R.,Prochaska J.X.; Murphy M.T.; Cantalupo S.
IVOA id: ivo://cds.vizier/j/mnras/524/3474

Stellar properties of z ~ 6.5-8 CEERS galaxies

2026-10-09T14:25:32Z

Description: Spitzer/Infrared Array Camera (IRAC) imaging has revealed that the brightest z ~ 7-8 galaxies often exhibit young ages and strong nebular line emission, hinting at high ionizing efficiency among early galaxies. However, IRAC's limited sensitivity has long hindered efforts to study the fainter, more numerous population often thought largely responsible for reionization. Here, we use Cosmic Evolution Early Release Science (CEERS) JWST/NIRCam data to characterize 116 ultraviolet (UV)-faint (median MUV = -19.5) z ~ 6.5-8 galaxies. The spectral energy distributions are typically dominated by young (~10-50 Myr), low-mass (M* ~ 10^8^ M_{sun}_) stellar populations, and we find no need for extremely high stellar masses (~10^11^ M_{sun}_). Considering previous studies of UV-bright (M_UV_ ~ -22) z ~ 7-8 galaxies, we find evidence for a strong (5-10 times) increase in specific star formation rate (sSFR) toward lower luminosities (median sSFR = 103 Gyr^-1^ in CEERS). The larger sSFRs imply a more dominant contribution from OB stars in the relatively numerous UV-faint population, perhaps suggesting that these galaxies are very efficient ionizing agents (median {xi}_ion_ = 10^25.7^ erg^-1^ Hz). In spite of the much larger sSFRs, we find little increase in [O III] + H_{beta}_ equivalent widths towards fainter M_UV_ (median =~ 780 {AA}). If confirmed, this may indicate that a substantial fraction of our CEERS galaxies possess extremely low metallicities (<~3 per cent Z_{sun}_) where [O III] emission is suppressed. Alternatively, high ionizing photon escape fractions or bursty star formation histories can also weaken the nebular lines in a subset of our sample. While the majority of galaxies in our sample are very blue (median {beta} = -2.0), we identify a significant tail of very dusty galaxies ({beta} ~ -1) at =~ 0.5 L^*^_UV_ which may contribute significantly to the z ~ 7-8 star formation rate density.
Author(s): Endsley R.; Stark D.P.; Whitler L.; Topping M.W.; Chen Z.; Plat A.,Chisholm J.; Charlot S.
IVOA id: ivo://cds.vizier/j/mnras/524/2312

Chemicals/kinematics and ages of MW stars

2026-10-09T14:20:17Z

Description: The Milky Way has distinct structural stellar components linked to its formation and subsequent evolution, but disentangling them is non-trivial. With the recent availability of high-quality data for a large numbers of stars in the Milky Way, it is a natural next step for research in the evolution of the Galaxy to perform automated explorations with unsupervised methods of the structures hidden in the combination of large-scale spectroscopic, astrometric, and asteroseismic data sets. We determine precise stellar properties for 21076 red giants, mainly spanning 2-15 kpc in Galactocentric radii, making it the largest sample of red giants with measured asteroseismic ages available to date. We explore the nature of different stellar structures in the Galactic disc by using Gaussian mixture models as an unsupervised clustering method to find substructure in the combined chemical, kinematic, and age subspace. The best-fitting mixture model yields four distinct physical Galactic components in the stellar disc: the thin disc, the kinematically heated thin disc, the thick disc, and the stellar halo. We find hints of an age asymmetry between the Northern and Southern hemisphere, and we measure the vertical and radial age gradient of the Galactic disc using the asteroseismic ages extended to further distances than previous studies.
Author(s): Stokholm A.; Aguirre Borsen-Koch V.; Stello D.; Hon M.; Reyes C.
IVOA id: ivo://cds.vizier/j/mnras/524/1634

High-confidence Galactic RSGs

2026-10-09T12:54:45Z

Description: Red supergiants (RSGs), representing a kind of massive young stellar population, have rarely been used to probe the structure of the Milky Way, mainly due to the long-standing scarcity of Galactic RSG samples. The Gaia BP/RP spectra (hereafter XP), which cover a broad wavelength range, provide a powerful tool for identifying RSGs. In this work, we develop a feedforward neural network classifier that assigns to each XP spectrum a probability of being an RSG, denoted as P(RSG). We perform 10 independent runs with randomly divided training and validation sets, and apply each run to all XP spectra of stars with G<12mag. By selecting sources with P(RSG)>=0.9, 10 high-confidence candidate samples are obtained. A star is considered a true Galactic RSG only if it appears in at least eight of these samples, yielding a final catalog of 2436 objects. These RSGs show a clear spatial correlation with OB stars and trace the Galactic spiral arms well, confirming the reliability of our classification, and highlighting their potential to serve as powerful tracers of the Milky Way's structure.
Author(s): Zhang Z.; Jiang B.; Ren Y.
IVOA id: ivo://cds.vizier/j/apj/998/307

Stars in Palomar 5 stellar stream

2026-10-09T12:54:04Z

Description: We explore constraints on the Milky Way dark matter halo oblateness using three stellar streams from globular clusters NGC3201, M68, and Palomar 5. Previous constraints on the gravitational potential from dynamical equilibrium of stellar populations and distant Milky Way satellites are included. We model the dark halo as axisymmetric with axis ratio q^h^_{rho}_ and four additional free parameters of a two power-law density profile. The halo axis ratio, while barely constrained by the NGC3201 stream alone, is required to be close to spherical by the streams of Palomar 5 (q^h^_{rho}_ = 1.01+/-0.09) and M68 (q^h^_{rho}_ = 1.14^+0.21^_-0.14_), the latter allowing a more prolate shape. The three streams together are well fitted with a halo axis ratio q^h^_{rho}_ = 1.06 +/- 0.06 and core radius ~20 kpc. Our estimate of the halo shape agrees with previous studies using other observational data and is in tension with cosmological simulations, predicting that most spiral galaxies have oblate dark matter haloes with the short axis perpendicular to the disc. We discuss why the impact of the Magellanic Clouds tide is too small to change our conclusion on the halo axis ratio. We note that dynamical equilibrium of a spherical halo in the oblate disc potential implies an anisotropic dark matter velocity dispersion, larger along the vertical direction than the horizontal ones, which should relate to the assembly history of the Milky Way.
Author(s): Palau C.G.; Miralda-Escude J.
IVOA id: ivo://cds.vizier/j/mnras/524/2124

M38 OpC star members and Gaia/SDSS photometry

2026-10-09T08:59:52Z

Description: Our recent multiband photometric study of the colour width of the lower main sequence of the open cluster M37 has revealed the presence of a sizeable initial chemical composition spread in the cluster. If initial chemical composition spreads are common amongst open clusters, this would have major implications for cluster formation models and the foundation of the chemical tagging technique. Here, we present a study of the unevolved main sequence of the open cluster M38, employing Gaia DR3 photometry and astrometry, together with newly acquired Sloan photometry. We have analysed the distribution of the cluster's lower main-sequence stars with a differential colour-colour diagram made of combinations of Gaia and Sloan magnitudes, like in the study of M37. We employed synthetic stellar populations to reproduce the observed trend of M38 stars in this diagram and found that the observed colour spreads can be explained simply by the combined effect of differential reddening across the face of the cluster and the presence of unresolved binaries. There is no need to include in the synthetic sample a spread of initial chemical composition as instead necessary to explain the main sequence of M37. Further photometric investigations like ours, as well as accurate differential spectroscopic analyses on large samples of open clusters, are necessary to understand whether chemical abundance spreads are common among the open cluster population.
Author(s): Griggio M.; Salaris M.; Bedin L.R.; Cassisi S.
IVOA id: ivo://cds.vizier/j/mnras/523/5148

XP-TEAL. II. Gaia-HELIX catalogue

2026-10-09T08:32:11Z

Description: With Gaia's third Data Release (DR3), low-resolution BP/RP (XP) spectra became available for more than 219 million sources. In previous work, we developed a fast method for detecting absorption and emission lines while measuring their equivalent widths directly from the XP spectral coefficients. We conduct a systematic search for H{alpha} emitters in the Gaia DR3 XP spectra. We measured the equivalent width of the Balmer H{alpha} line for all sources with Gaia XP spectra and selected an initial sample of 556100 sources depicting an H{alpha} emission-like feature at 2{sigma} level or above. Using a semi-supervised classifier complemented by manual spectral labelling, we removed sources that merely masqueraded as emission-line stars. We find that 95% of the initial candidates are most likely cool M-type stars, where a molecular absorption band gives rise to a local maximum that can mimic H{alpha} emission. Subsequently, 28394 sources were flagged as bona fide H{alpha} emitters using the Gaia DR3 XP spectra. The majority are Be-like candidates (26287), M-type emission-line stars (717), Herbig Ae/Be candidates (525), quasi-stellar objects (204), Wolf-Rayet stars (177), cataclysmic variables (51), and carbon stars (18), among other sources. Our equivalent widths and stellar classifications agree well with results from higher-resolution studies and recent Gaia XP spectra-based catalogues. Ground- based spectroscopic follow-up for some of the newly found H{alpha} emitters reinforces our confidence in the catalogue.
Author(s): Malhotra S.; Weiler M.; Anders F.; Carrasco J.M.; Garcia-Moreno G.,Jordi C.; Blagorodnova N.; Castro-Ginard A.; Castaneda J.; Boix F.,Luri X.
IVOA id: ivo://cds.vizier/j/a+a/714/a90

Abell 2034 MeerKAT Stoked I images

2026-10-09T08:25:12Z

Description: We present MeerKAT observations of the galaxy cluster Abell 2034, a massive (M_500_=5.21x10^14^M_{sun}_) nearby cluster in a merging state. Previous observations at 144MHz have shown that the cluster exhibits a pl ethora of diffuse emission, with multiple diffuse sources of uncertain classification because of the lack of spectral and polarimetric observations. MeerKAT multifrequency observations, centered at 816MHz and 1.28GHz, together with archival low-frequency LOFAR observations at 144MHz have enabled us to shed light on the properties of these sources. The polarization properties and spectral index information lead us to conclude that the cluster hosts one radio relic, a source with a very steep spectrum, previously classified as candidate relic, along with filaments of very steep emission around the tailed radio galaxies identified at low frequencies. The presence of a radio halo is confirmed and its spectrum displays hints of a curvature between 144MHz ad 1.28GHz. We used the polarimetric data in the L band, together with the model of the gas density derived from X-ray observations to constrain the magnetic field in the intracluster medium. We assumed a radially symmetric magnetic field model, whose strength declines with the cluster gas density as B(r){prop.to}n_e(r)^0.5^. We normalized its strength within R_500_ (B_500_). We found that B_500_=1muG best explains the Faraday depth properties of the cluster, although the detection of sources close to the cluster center would be crucial to discriminate among different values. We conclude that the cluster Abell 2034 exhibits diffuse emission with complex morphologies that do not follow the historical categories of halos and relics. Deep multifrequency and polarimetric observations are fundamental to understanding their origin.
Author(s): Bonafede A.; Balboni M.; Pratt G.W.; Bartalucci I.; Rudnick L.,Riseley C.J.; Stuardi C.; Hugo B.; Bernardi G.; Brueggen M.; Brunetti G.,Cassano R.; De Gasperin F.; Gastaldello F.; Knowles K.; Loi F.,Shimwell T.; van Weeren R.J.
IVOA id: ivo://cds.vizier/j/a+a/714/a237

Rovibronic data of N2

2026-10-09T08:24:12Z

Description: Accurate radiative transition data for molecular nitrogen are required for modeling atmospheric and astrophysical spectra involving electronically excited N2. We aim to determine the rovibronic energy levels, transition dipole moments, and Einstein A coefficients associated with dipole-allowed radiative transitions among the 11 lowest-lying electronic states of N2, and to provide a comprehensive database of these transitions. Rovibronic energy levels and transition dipole moments were computed from first principles. Einstein A coefficients were calculated for both vibronic and rotationally resolved transitions. The resulting radiative transition data were used to model rotationally resolved spectra originating from the B3Pi_g and C3Pi_u states. Doppler, collisional, and radiative broadening at 300 K were included in the simulations. The calculated Einstein coefficients for vibronic transitions show excellent agreement with the available experimental data, validating the computed potential energy curves and transition dipole moments. This agreement supports the reliability of the rotationally resolved coefficients and the predictions for transitions for which no experimental data are available. A comprehensive numerical database of radiative transitions between the rovibronic levels of the 11 lowest electronic states of N2 is provided. The computed data enable detailed modeling of rotationally resolved molecular nitrogen spectra.
Author(s): Hammami C.; Ayouz M.; Kokoouline V.
IVOA id: ivo://cds.vizier/j/a+a/714/a185

Cataclysmic variables from SRG/eROSITA

2026-10-09T08:21:55Z

Description: The X-ray all-sky surveys performed with eROSITA on the Spektrum-Roentgen-Gamma (SRG) mission offer a unique opportunity to generate large samples of all kinds of X-ray emitters. Here we focus on a minority population among the X-ray point sources: the cataclysmic variables (CVs). We aim to generate large samples of CVs selected from the SRG/eROSITA surveys to address fundamental questions about binary evolution and the role of magnetic fields in CV evolution and their contribution to the Galactic Ridge X-ray emission (GRXE). We trained a random-forest (RF) classifier based on combined X-ray and optical properties to select CV candidates from the first eROSITA X-ray all-sky survey (eRASS1). Follow-up spectroscopy to securely identify the objects was performed on a subset of the selected candidates using telescopes at the northern and southern hemispheres. Newly identified CVs were further analyzed to determine their likely subtype with the help of dedicated follow-up photometry, spectroscopy, and archival resources. We identified 156 CVs of almost all subtypes covering a wide range of distances (between 170pc and several kiloparsecs), absolute magnitudes (G=4.5-12) and X-ray luminosities (logLX(erg/s)(0.2-2.3keV)=29.6-33.3). For most objects, their CV nature is reported here for the first time. For 40 objects periods were determined, which were regarded as their likely orbital periods. These range from 79.2 min, at the CV minimum period, to almost 22 hours. Seven objects were found to be eclipsing, a lower limit to the actual number due to the current lack of dedicated follow-up observations. A further five objects show cyclotron or Zeeman features, which allowed us to determine their field strengths. A soft component was found in 14 CVs, and all were regarded as magnetic. The sample comprises X-ray-luminous objects, which are excellent new intermediate-polar candidates; these are thought to be main contributors to the GRXE. The new method of selecting CVs from eRASS1 was found to be superior to other methods described in the literature, and the new CVs were used to further refine the method. This work demonstrates the feasibility of constructing comprehensive CV samples through follow-up spectroscopy of SRG/eROSITA X-ray sources. It has also demonstrated the potential to uncover rare objects, which are of scientific interest on their own.
Author(s): Schwope A.D.; Brink J.; Buckley D.A.H.; Cuneo V.A.; Friedrich S.,Hernandez-Diaz S.; Knauff K.; Kurpas J.; Lamer G.; Potter S.B.,Pradeep K.G.; Schreiber M.R.; Stelzer B.; Thorstensen J.R.; Tubin-Arenas D.
IVOA id: ivo://cds.vizier/j/a+a/714/a180