- ID:
- ivo://CDS.VizieR/J/A+AS/145/111
- Title:
- HDF-South catalogue of galaxies
- Short Name:
- J/A+AS/145/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of galaxies in the HDF-S, created using the public version 1 images of the WFPC2 data. We created a catalogue with 4 pass-band (I(814), V(606), B(450), U(300). In V(606), B(450), U(300) and I(814), for each galaxy the catalogue gives photometric parameters. For the I(814), we estimated also the colours and for I(814)<26, the petrosian radius, the mean surface brightness within the petrosian radius, light concentration indexes, that is C_eta_ and C_abr_, and the asymmetry index as computed by Abraham software.
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- ID:
- ivo://CDS.VizieR/J/AJ/122/2205
- Title:
- HDF-South K photometric redshift catalog
- Short Name:
- J/AJ/122/2205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from the Faint Infra-Red Extragalactic Survey of the Hubble Deep Field South (HDF-S). Using a combination of deep near-infrared (NIR) data obtained with the Infrared Spectrograph and Array Camera at the VLT and the WFPC2 Hubble Space Telescope data, we construct a K-band-selected sample which is 50% and 90% complete for K_s,AB_<=23.5 and K_s,AB_<=22.0, respectively, where the magnitudes are measured over a 2.0" diameter aperture. For z<=3, our selection by the K-band flux chooses galaxies based on wavelengths redder than the rest-frame V band, and so selects them in a way that is less dependent on their current star formation rates than selection in the rest-frame UV.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/172
- Title:
- HeCS-red: Hectospec surveys of redMaPPer clusters
- Short Name:
- J/ApJ/862/172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use dense redshift surveys to explore the properties of galaxy clusters selected from the redMaPPer catalog. Our new survey, Hectospec Cluster Survey of red-sequence-selected clusters (HeCS-red), includes 10589 new or remeasured redshifts from MMT/Hectospec observations of 27 redMaPPer clusters at redshifts z=0.08-0.25 with large estimated richnesses (richness estimate {lambda}>64). Our spectra confirm that each candidate cluster corresponds to a large overdensity in redshift space. The redMaPPer photometric redshifts have a slight bias toward higher redshifts. We measure the relation between velocity dispersion {sigma}p and {lambda}. The relation shows intrinsic scatter of 24% (and a range of 2x) in velocity dispersion at fixed richness. We extend our analysis to HeCS-red-ext, a sample that includes several clusters selected by X-ray flux or Sunyaev-Zeldovich signal. The heterogeneous sample of 121 clusters in HeCS-red-ext shows similar intrinsic scatter in the {sigma}p-{lambda} relation as the HeCS-red sample, but the range of {sigma}p at fixed richness increases to 3x. We evaluate the membership probability estimates Pmem for individual galaxies provided by redMaPPer. The spectroscopic membership fraction is larger than Pmem for 0.05<=P_mem_<=0.7; conversely, the spectroscopic membership fraction is smaller than P_mem_ at P_mem_>=0.8. We compare spectroscopic richness estimates with redMaPPer richness estimates and find good agreement on average, but a range of a factor of two in spectroscopic richness at fixed redMaPPer richness. Overall, within the high-richness and low-redshift cut of our sample, spectroscopically estimated parameters such as velocity dispersion correlate well with photometric richness estimates, although the relations contain substantial scatter.
- ID:
- ivo://CDS.VizieR/J/AJ/158/192
- Title:
- He II emission from Wolf-Rayet stars in MW & LMC
- Short Name:
- J/AJ/158/192
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We calibrated a technique to measure dust attenuation in star-forming galaxies. The technique utilizes the stellar-wind lines in Wolf-Rayet stars, which are widely observed in galaxy spectra. The He II 1640 and 4686 features are recombination lines whose ratio is largely determined by atomic physics. Therefore they can serve as a stellar dust probe in the same way as the Balmer lines are used as a nebular probe. We measured the strength of the He II 1640 line in 97 Wolf-Rayet stars in the Galaxy and the Large Magellanic Cloud. The reddening corrected fluxes follow a tight correlation with a fixed ratio of 7.76 for the He II 1640 to 4686 line ratio. Dust attenuation decreases this ratio. We provide a relation between the stellar E(B-V) and the observed line ratio for several attenuation laws. Combining this technique with the use of the nebular Balmer decrement allows the determination of the stellar and nebular dust attenuation in galaxies and can probe its effects at different stellar age and mass regimes, independently of the initial mass function and the star formation history. We derived the dust reddening from the He II line fluxes and compared it to the reddening from the Balmer decrement and from the slope of the ultraviolet continuum in two star-forming galaxies. The three methods result in dust attenuations which agree to within the errors. Future application of this technique permits studies of the stellar dust attenuation compared to the nebular attenuation in a representative galaxy sample.
- ID:
- ivo://CDS.VizieR/J/ApJ/847/81
- Title:
- HeII photoionization rates of quasars
- Short Name:
- J/ApJ/847/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The HeII transverse proximity effect-enhanced HeII Ly{alpha} transmission in a background sightline caused by the ionizing radiation of a foreground quasar-offers a unique opportunity to probe the morphology of quasar-driven HeII reionization. We conduct a comprehensive spectroscopic survey to find z~3 quasars in the foreground of 22 background quasar sightlines with Hubble Space Telescope/COS HeII Ly{alpha} transmission spectra. With our two-tiered survey strategy, consisting of a deep pencil-beam survey and a shallow wide-field survey, we discover 131 new quasars, which we complement with known SDSS/BOSS quasars in our fields. Using a restricted sample of 66 foreground quasars with inferred HeII photoionization rates greater than the expected UV background at these redshifts ({Gamma}_QSO_^HeII^>5x10^-16^s^-1^) we perform the first statistical analysis of the HeII transverse proximity effect. Our results show qualitative evidence for a large object-to-object variance: among the four foreground quasars with the highest {Gamma}_QSO_^HeII^ only one (previously known) quasar is associated with a significant HeII transmission spike. We perform a stacking analysis to average down these fluctuations, and detect an excess in the average HeII transmission near the foreground quasars at 3{sigma} significance. This statistical evidence for the transverse proximity effect is corroborated by a clear dependence of the signal strength on {Gamma}_QSO_^HeII^. Our detection places a purely geometrical lower limit on the quasar lifetime of t_Q_>25Myr. Improved modeling would additionally constrain quasar obscuration and the mean free path of HeII-ionizing photons.
- ID:
- ivo://CDS.VizieR/J/ApJ/885/74
- Title:
- 1340 Helium rich white dwarfs in the Gaia era
- Short Name:
- J/ApJ/885/74
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- We present an analysis of 1023 DBZ/DZ(A) and 319 DQ white dwarf stars taken from the Montreal White Dwarf Database. This represents a significant increase over the previous comprehensive studies on these types of objects. We use new trigonometric parallax measurements from the Gaia second data release, together with photometry from the Sloan Digital Sky Survey, Pan-STARRS, Gaia, or BVRI from the literature, which allow the determination of the mass for the majority of the objects in our sample. We use the photometric and spectroscopic techniques with our recently improved model atmospheres code, which include high-density effects, to accurately determine the effective temperature, surface gravity, and heavy-element abundances for each object. We study the abundance of hydrogen in DBZ/DZ white dwarfs and the properties of the accreted planetesimals. We explore the nature of the second sequence of DQ stars using proper motions from Gaia and highlight evidence of crystallization in massive DQ stars. We also present mass distributions for both spectral types. Finally, we discuss the implications of our findings in the context of the spectral evolution of white dwarfs and provide the atmospheric parameters for each star.
- ID:
- ivo://CDS.VizieR/J/AJ/118/1043
- Title:
- Herbig Ae/Be stars catalog
- Short Name:
- J/AJ/118/1043
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVR photometric monitoring of Herbig Ae/Be stars and some related objects has been carried out at Maidanak Observatory in Uzbekistan since 1983. More than 71,000 observations of about 230 stars have been obtained and are made available for anonymous ftp. Virtually all Herbig Ae/Be stars observed are irregular variables (called "UXors" after UX Ori), but there is a wide range of amplitudes from barely detectable to more than 4mag in V. Our data confirm the results of previous studies, which indicate that large-amplitude variability is confined to stars with spectral types later than B8. The distribution of variability ranges is quite similar to what is seen in classical T Tauri stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/236/30
- Title:
- Herschel-ATLAS (H-ATLAS) DR2
- Short Name:
- J/ApJS/236/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) is a survey of 660deg^2^ with the PACS and SPIRE cameras in five photometric bands: 100, 160, 250, 350, and 500{mu}m. This is the second of three papers describing the data release for the large fields at the south and north Galactic poles (NGP and SGP). In this paper we describe the catalogs of far-infrared and submillimeter sources for the NGP and SGP, which cover 177.1deg^2^ and 303.4deg^2^, respectively. The catalogs contain 118980 sources for the NGP field and 193527 sources for the SGP field detected at more than 4{sigma} significance in any of the 250, 350, or 500{mu}m bands. The source detection is based on the 250{mu}m map, and we present photometry in all five bands for each source, including aperture photometry for sources known to be extended. The rms positional accuracy for the faintest sources is about 2.4" in both RA and DEC. We present a statistical analysis of the catalogs and discuss the practical issues-completeness, reliability, flux boosting, accuracy of positions, accuracy of flux measurements-necessary to use the catalogs for astronomical projects.
- ID:
- ivo://CDS.VizieR/J/A+A/572/A90
- Title:
- Herschel-VVDS-CFHTLS-D1 detections
- Short Name:
- J/A+A/572/A90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate of the properties of ~2000 Herschel/SPIRE far-infrared-selected galaxies from 0<z<4 in the CFHTLS-D1 field. Using a combination of extensive spectroscopy from the VVDS and ORELSE surveys, deep multiwavelength imaging from CFHT, VLA, Spitzer, XMM-Newton, and Herschel, and well-calibrated spectral energy distribution fitting, Herschel-bright galaxies are compared to optically-selected galaxies at a variety of redshifts. Herschel-selected galaxies are observed to span a range of stellar masses, colors, and absolute magnitudes equivalent to galaxies undetected in SPIRE. Though many Herschel galaxies appear to be in transition, such galaxies are largely consistent with normal star-forming galaxies when rest-frame colors are utilized. The nature of the star-forming "main sequence" is studied and we warn against adopting this framework unless the main sequence is determined precisely. Herschel galaxies at different total infrared luminosities (L_TIR_) are compared. Bluer optical colors, larger nebular extinctions, and larger contributions from younger stellar populations are observed for galaxies with larger L_TIR_, suggesting that low-L_TIR_ galaxies are undergoing rejuvenated starbursts while galaxies with higher L_TIR_ are forming a larger percentage of their stellar mass. A variety of methods are used to select powerful active galactic nuclei (AGN). Galaxies hosting all types of AGN are observed to be undergoing starbursts more commonly and vigorously than a matched sample of galaxies without powerful AGN and, additionally, the fraction of galaxies with an AGN increases with increasing SFR at all redshifts. At all redshifts (0<z<4) the most prodigious star-forming galaxies are found to contain the highest fraction of powerful AGN. For redshift bins that allow a comparison (z>0.5), the highest L_TIR_ galaxies in a given redshift bin are unobserved by SPIRE at subsequently lower redshifts, a trend linked to downsizing. In conjunction with other results, this evidence is used to argue for prevalent AGN-driven quenching in starburst galaxies across cosmic time.
- ID:
- ivo://CDS.VizieR/J/ApJ/842/133
- Title:
- HI-bearing ultra-diffuse ALFALFA galaxies
- Short Name:
- J/ApJ/842/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 115 very low optical surface brightness, highly extended, HI-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently discovered "ultra-diffuse" galaxies (UDGs). However, these systems are bluer and have more irregular morphologies than other UDGs, are isolated, and contain significant reservoirs of HI. We find that while these sources have normal star formation rates for HI-selected galaxies of similar stellar mass, they have very low star formation efficiencies. We further present deep optical and HI-synthesis follow-up imaging of three of these HI-bearing ultra-diffuse sources. We measure HI diameters extending to ~40kpc, but note that while all three sources have large HI diameters for their stellar mass, they are consistent with the HI mass-HI radius relation. We further analyze the HI velocity widths and rotation velocities for the unresolved and resolved sources, respectively, and find that the sources appear to inhabit halos of dwarf galaxies. We estimate spin parameters, and suggest that these sources may exist in high spin parameter halos, and as such may be potential HI-rich progenitors to the ultra-diffuse galaxies observed in cluster environments.
