Information on Service 'Hamburg/ESO Survey Browser Service'

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The Hamburg/ESO survey (HES) is a digital objective prism survey covering the total southern extragalactic sky. It is based on Kodak IIIa-J plates which have been taken with the 1m ESO Schmidt telescope and its 4° prism. The spectral coverage is 3200-5300 Å, at an resolution of 15 Å at H gamma. The magnitude range covered is roughly between 18.5 and 11 mag in B_J.

This is a collection of uniformly reduced spectra prepared by Norbert Christlieb. It is also intended as a sort-of resolver for HES names (“identifiers“) like ”HE 2301-7732”; unfortunately, these identifiers are not unique. You will need to apply domain knowledge in order to find the object actually being referred to when resolving an identifier of this sort.

For a list of all services and tables belonging to this service's resource, see Information on resource 'Hamburg/ESO Survey Spectra'

Overview

You can access this service using:

Coverage

Intervals of messenger energies reflected in this resource: 2.88335 3.82667 eV

This resource is not (directly) published. This can mean that it was deemed too unimportant, for internal use only, or is just a helper for a published service. Equally likely, however, it is under development, abandoned in development or otherwise unfinished. Exercise some caution.

Other services provided on the underlying data include:

Input Fields

The following fields are available to provide input to the service (with some renderers, some of these fields may be unavailable):

NameTable Head DescriptionUnitUCD
hes_id HES id Alternative, more precise HES identifier consisting of the first seven digits of the right ascension at equinox 2000.0, the first six digits of the declination at equinox 2000.0, the plate quarter (a, b, c, or d), and the HES plate number. Example: For HE 0107−5240, which is located on quarter c of plate 2052 and at coordinates α = 01h09m29s.1, δ = −52◦24'34'', the HESid is HE0109291m522434c2052. N/A meta.id
hes_name HES name HES designation, consisting of the letters 'HE', the first four digits of the right ascension at equinox B1950.0, and the first four digits of the declination at equinox B1950.0. Example: HE 2301-7732. N/A meta.id;meta.main
ssa_location Location ICRS location of aperture center deg pos.eq

Default Output Fields

The following fields are contained in the output by default. More fields may be available for selection; these would be given below in the VOTable output fields.

NameTable Head DescriptionUnitUCD
accref Product key Access key for the data N/A meta.ref.url;meta.dataset
bj_dss B_J Magnitude in the B_J band, measured on the relevant DSS-I plate and calibrated to a small number of reference stars. Note bj mag phot.mag;em.opt.B
hes_name HES name HES designation, consisting of the letters 'HE', the first four digits of the right ascension at equinox B1950.0, and the first four digits of the declination at equinox B1950.0. Example: HE 2301-7732. Note hes N/A meta.id;meta.main
location_dec Dec N/A deg pos.eq.dec;meta.main
location_ra RA N/A deg pos.eq.ra;meta.main
objtype Type Morphological source type [stars/ext/bright], discriminating between different extraction schemes used for the spectra, also impacting the sizes of the actual extraction apertures. 'stars' means point source, 'ext' means extended object (mostly galaxies), 'bright' means sources with partly saturated spectra, typically occuring for stars brighter than B_J ≈ 14 mag Note ob N/A src.class
ovl Overlap Binary flag [0/1]. A value of 1 signals that the spectrum suffers contamination from another object located in dispersion direction. Note ovl N/A meta.code.qual
sn_bj SNR Average signal to noise ratio per pixel of the HES spectra in the B_J band. See Christlieb et al. (2001, 2001A&A...366..898C) for a description of how this parameter was estimated. N/A stat.snr
strc1 C1 Stroemgren c1 index measured in the HES spectrum. N/A spect.index;em.opt

VOTable Output Fields

The following fields are available in VOTable output. The verbosity level is a number intended to represent the relative importance of the field on a scale of 1 to 30. The services take a VERB argument. A field is included in the output if their verbosity level is less or equal VERB*10.

NameTable Head DescriptionUnitUCD Verb. Level
accref Product key Access key for the data N/A meta.ref.url;meta.dataset 1
hes_name HES name HES designation, consisting of the letters 'HE', the first four digits of the right ascension at equinox B1950.0, and the first four digits of the declination at equinox B1950.0. Example: HE 2301-7732. Note hes N/A meta.id;meta.main 1
ra RA Right ascension for equinox J2000. The coordinates were derived from the DSS-I, and they are typically accurate to within 1 arcsec (rms). deg pos.eq.ra;meta.main 1
dec Dec Declination for equinox J2000. The coordinates were derived from the DSS-I, and they are typically accurate to within 1 arcsec (rms). deg pos.eq.dec;meta.main 1
ssa_location Location ICRS location of aperture center deg pos.eq 5
ssa_dateObs Date Obs. Midpoint of exposure (MJD) d time.epoch 5
ssa_timeExt Exp. Time Exposure duration s time.duration 5
ssa_length Length Number of points in the spectrum N/A N/A 5
objtype Type Morphological source type [stars/ext/bright], discriminating between different extraction schemes used for the spectra, also impacting the sizes of the actual extraction apertures. 'stars' means point source, 'ext' means extended object (mostly galaxies), 'bright' means sources with partly saturated spectra, typically occuring for stars brighter than B_J ≈ 14 mag Note ob N/A src.class 5
mag_b_hes Mag. B Approximate photographic magnitude in the Johnson B band derived by combining the B_J magnitude and the B-V colour. Note b mag phot.mag;em.opt.b 5
accsize File size Size of the data in bytes byte N/A 11
ssa_dstitle Title A compact and descriptive designation of the dataset. N/A meta.title;meta.dataset 15
ssa_creatorDID C. DID Dataset identifier assigned by the creator N/A meta.id 15
ssa_pubDID P. DID Dataset identifier assigned by the publisher N/A meta.ref.ivoid 15
ssa_cdate Proc. Date Processing/Creation date N/A time;meta.dataset 15
ssa_pdate Pub. Date Date last published. N/A N/A 15
ssa_bandpass Bandpass Bandpass (i.e., rough spectral location) of this dataset; this should be the most appropriate term from the vocabulary http://www.ivoa.net/rdf/messenger. N/A instr.bandpass 15
ssa_cversion C. Version Creator assigned version for this dataset (will be incremented when this particular item is changed). N/A meta.version;meta.dataset 15
ssa_targname Object Common name of object observed. N/A meta.id;src 15
ssa_targclass Ob. cls Object class (star, QSO,...; use Simbad object classification http://simbad.u-strasbg.fr/simbad/sim-display?data=otypes if at all possible) N/A src.class 15
ssa_redshift z Redshift of target object N/A src.redshift 15
ssa_targetpos Obj. pos Equatorial (ICRS) position of the target object. N/A pos.eq;src 15
ssa_snr SNR Signal-to-noise ratio estimated for this dataset N/A stat.snr 15
ssa_aperture Aperture Angular diameter of aperture deg phys.angSize;instr.fov 15
ssa_specmid Mid. Band Midpoint of region covered in this dataset m instr.bandpass 15
ssa_specext Bandwidth Width of the spectrum m instr.bandwidth 15
ssa_specstart Band start Lower value of spectral coordinate m em.wl;stat.min 15
ssa_specend Band end Upper value of spectral coordinate m em.wl;stat.max 15
ssa_csysName Sys System RA and Dec are given in N/A N/A 15
ssa_spectralucd UCD(spectral) UCD of the spectral column in the spectra served; when you have wavelengths, use em.wl for vacuum wavelengths, em.wl;obs.atmos for air wavelengths. N/A meta.ucd 15
ssa_spectralunit unit(spectral) Unit of the spectral column N/A meta.unit 15
ssa_fluxucd UCD(flux) UCD of the flux column N/A meta.ucd 15
ssa_fluxunit unit(flux) Unit of the flux column N/A meta.unit 15
ssa_publisher Publisher Publisher of the datasets included here. N/A meta.curation 15
ssa_creator Creator Creator of the datasets included here. N/A N/A 15
ssa_collection Collection A short handle naming the collection this spectrum belongs to. N/A N/A 15
ssa_instrument Instrument Instrument or code used to produce these datasets N/A meta.id;instr 15
ssa_datasource Src Method of generation for the data (one of survey, pointed, theory, custom, artificial). N/A N/A 15
ssa_creationtype Using Process used to produce the data (archival, cutout, filtered, mosaic, projection, spectralExtraction, or catalogExtraction) N/A N/A 15
ssa_reference Ref. URL or bibcode of a publication describing this data. N/A meta.bib.bibcode 15
ssa_fluxStatError Err. flux Statistical error in flux N/A stat.error;phot.flux.density;em 15
ssa_fluxSysError Sys. Err flux Systematic error in flux N/A stat.error.sys;phot.flux.density;em 15
ssa_fluxcalib Calib Flux Type of flux calibration (ABSOLUTE, CALIBRATED, RELATIVE, NORMALIZED, or UNCALIBRATED). N/A N/A 15
ssa_binSize Spect. Bin Bin size in wavelength m em.wl;spect.binSize 15
ssa_spectStatError Err. Spect Statistical error in wavelength m stat.error;em 15
ssa_spectSysError Sys. Err. Spect Systematic error in wavelength m stat.error.sys;em 15
ssa_speccalib Calib. Spect. Type of wavelength calibration N/A meta.code.qual 15
ssa_specres Spec. Res. Resolution (in meters of wavelength) on the spectral axis m spect.resolution;em.wl 15
ssa_spaceError Err. Spc Statistical error in position deg stat.error;pos.eq 15
ssa_spaceCalib Calib. Spc Type of calibration in spatial coordinates N/A meta.code.qual 15
ssa_spaceRes Res. Spc Spatial resolution of data deg pos.angResolution 15
hes_id HES id Alternative, more precise HES identifier consisting of the first seven digits of the right ascension at equinox 2000.0, the first six digits of the declination at equinox 2000.0, the plate quarter (a, b, c, or d), and the HES plate number. Example: For HE 0107−5240, which is located on quarter c of plate 2052 and at coordinates α = 01h09m29s.1, δ = −52◦24'34'', the HESid is HE0109291m522434c2052. N/A meta.id 15
field ESO-SRC Field number in the ESO/SRC (or ESO/SERC) sky atlas. N/A meta.id;obs.field 15
ovl Overlap Binary flag [0/1]. A value of 1 signals that the spectrum suffers contamination from another object located in dispersion direction. Note ovl N/A meta.code.qual 15
bj_dss B_J Magnitude in the B_J band, measured on the relevant DSS-I plate and calibrated to a small number of reference stars. Note bj mag phot.mag;em.opt.B 15
sn_bj SNR Average signal to noise ratio per pixel of the HES spectra in the B_J band. See Christlieb et al. (2001, 2001A&A...366..898C) for a description of how this parameter was estimated. N/A stat.snr 15
b_v_hes B-V Approximate B-V colour derived from the half power points and calibrated against stellar samples with known multiband photometry. For details see Christlieb et al. (2001, 2001A&A...366..898C). mag phot.color;em.opt.b;em.opt.v 15
u_b_hes U-B Approximate U-B colour derived from the half power points and calibrated against stellar samples with known multiband photometry. For details see Christlieb et al. (2001, 2001A&A...366..898C). mag phot.color;em.opt.u;em.opt.b 15
strc1 C1 Stroemgren c1 index measured in the HES spectrum. N/A spect.index;em.opt 15
balmsum Balmer Sum of equivalent widths of Hbeta, Hgamma and Hdelta, measured in the HES spectrum by means of fits of Gaussians to these lines. N/A spect.index;em.opt 15
kphes Ca K index Line index for the Ca II K line measured in the HES spectrum (for details, see Christlieb et al. 2008, 2008A&A...484..721C). N/A spect.index;em.opt 15
gphes G Index Line index for the G band of CH measured in the HES spectrum (for details, see Christlieb et al. 2008, 2008A&A...484..721C). N/A spect.index;em.opt 15
c2idx1 C2 feature at 5165Á Band index for the C2 feature at 5165Á measured in the HES spectrum (for details, see Christlieb et al. 2001, 2001A&A...375..366C). mag spect.index;em.opt 15
c2idx2 C2 feature at 4737Á Band index for the C2 feature at 4737Á measured in the HES spectrum (for details, see Christlieb et al. 2001, 2001A&A...375..366C). mag spect.index;em.opt 15
cnidx1 CN feature at 4216Á Band index for the CN feature at 4216Á measured in the HES spectrum (for details, see Christlieb et al. 2001, 2001A&A...375..366C). mag spect.index;em.opt 15
cnidx3 CN feature at 3883Á Band index for the CN feature at 3883Á measured in the HES spectrum (for details, see Christlieb et al. 2001, 2001A&A...375..366C). mag spect.index;em.uv 15
mime Type MIME type of the file served N/A meta.code.mime 20
ssa_model Model Data model name and version N/A N/A 20
ssa_timeSI [Time] Time conversion factor in Osuna-Salgado convention. N/A N/A 20
ssa_spectralSI [Spectral] Spectral conversion factor in Osuna-Salgado convention N/A N/A 20
ssa_fluxSI [Flux] Flux/magnitude conversion factor in Osuna-Salgado convention N/A N/A 20
ssa_dstype Data type Type of data (spectrum, time series, etc) N/A N/A 20
owner Owner Owner of the data N/A N/A 25
embargo Embargo ends Date the data will become/became public yr N/A 25
plate Plate # Plate number of the HES objective prism plate in the ESO archive. N/A meta.id;instr.plate 25
quadrant Quadrant HES plate quadrant (i.e., a, b, c, or d). Note qua N/A meta.id;instr.plate 25
x_hpp1 HPP1 Spectral half power (or bisecting) point 1, measured in the HES objective-prism spectra in the wavelength region 320.0-484.0nm (2000A&A...358...77W). um N/A 25
x_hpp2 HPP2 Spectral half power (or bisecting) point 2, measured in the HES objective-prism spectra in the wavelength region 395.0-540.0nm (2000A&A...358...77W). um N/A 25
x_hpp3 HPP3 Spectral half power (or bisecting) point 3, measured in the HES objective-prism spectra in the wavelength region 352.0-505.0nm (2000A&A...358...77W). pixel N/A 25
x_qd QD Quartile distance; i.e., the distance between the points separating the first and the last 25% of the flux, as measured in the (not flux-calibrated) HES spectra (2000A&A...358...77W). um N/A 25
ssa_region Coverage Rough coverage based on location and aperture. N/A pos.outline;obs.field 30

Citation Info

VOResource XML (that's something exclusively for VO nerds)

Note b

The conversion between B_J and Johnson B is based on the transformation B = B_J + 0.28 · (B − V), valid for main sequence stars in the colour range −0.1 < (B − V) < 1.6 (Hewett et al. 1995, 1995AJ....109.1498H). The 1σ uncertainty of BHES is typically around 0.2 mag (Christlieb et al. 2001, 2001A&A...366..898C)."

Note bj

The photographic B_J band approximately covers the wavelength range 395.0-540.0nm. The photometric calibration of DSS magnitudes in all HES fields is only an approximate one, often based on just a few reference stars. (This was done before calibrated all-sky data became available.) The calibration relation was obtained as a Chebychev polynomial fit, which by construction gives meaningful results only over a predefined magnitude interval, typically around B_J ~ 10 as bright and B_J ~ 20 as faint limit. Outside of these intervals, in particular for brighter objects, the "calibrated" magnitudes can take almost arbitrary values. This divergence behaviour of the Chebychev polynomials varies from field to field but is similar for all objects within one field, so that the resulting magnitude distributions of very bright stars will show artificial clustering in magnitude space.

Note hes

This naming convention was originally adopted in 1990 when the HES was conceived as a wide-angle quasar survey, following similar schemes of earlier quasar surveys in the 1980s. Later it turned out that HES spectra could be used for several other purposes, in particular for stellar work, made it clear that the concept was not appropriate as multiple HES sources can have the same HE name. For this reason an alternative HES identifier was retrospectively added, see entry "hes_id".

Note ob

For point-like objects ("stars") a PSF-weighted extraction was used with an extraction aperture equal to the typical PSF FWHM, approximately 1 arcsec. The spectra of extended sources were extracted with Gaussian weights based on the actual width of the object, but with an upper limit on the extraction aperture of 9.5 arcsec full width (+/-4.75 arcsec) around the centroid trace. Partly saturated ("bright") objects were extracted as unweighted sum over 12 arcsec (full width). For these objects the spectral values are unreliable because of the saturation and not even approximately proportional to fluxes. Absorption lines can however still be discerned in many spectra.

Note ovl

In such cases the colour information of a HES spectrum is not to be trusted. Absorption or emission lines may still be traced correctly, depending on the nature of the overlapping source. Even for a flag value of 0, contamination by a faint object or an overlap at a wavelength shorter than 390.0 nm is still possible.

Note qua

As the ESO Schmidt plates were physically too large for the PDS scanner at Hamburg Observatory, they had to be scanned in four quarters with the following orientation: a refers to the South-Western (SW) quadrant of the scanned field, b to the SE, c to the NE, and d to the NW.