- ID:
- ivo://CDS.VizieR/J/ApJS/242/11
- Title:
- H{alpha} imaging survey of the 40% ALFALFA HI LSBGs
- Short Name:
- J/ApJS/242/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a narrow H{alpha}-band imaging survey of 357 low surface brightness galaxies (LSBGs) that are selected from the spring sky region of the 40% Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) HI Survey. All the H{alpha} images are obtained from the 2.16m telescope, operated by the Xinglong Observatory of the National Astronomical Observatories, Chinese Academy of Sciences. We provide the H{alpha} fluxes and derive the global star formation rates (SFRs) of LSBGs after the Galactic extinction, internal extinction, and [NII] contamination correction. Compared to normal star-forming galaxies, LSBGs have a similar distribution in the HI surface density ({Sigma}HI), but their SFRs and star formation surface density ({Sigma}SFR) are much lower. Our results show that the gas-rich LSBGs selected from the ALFALFA survey obviously deviate from the Kennicutt-Schmidt law, in the relation between the star formation surface density ({Sigma}SFR) and the gas surface density ({Sigma}gas). However, they follow the extended Schmidt law well when taking the stellar mass of the galaxy into consideration.
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- ID:
- ivo://CDS.VizieR/J/A+A/358/77
- Title:
- Hamburg/ESO survey for bright QSOs. III.
- Short Name:
- J/A+A/358/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Appendix to the above paper, containing the two large tables A.1 and B.1 described in the paper. Table A.1 gives the basic properties of the 207 survey fields used to construct the flux-limited sample, including field-dependent magnitude limits and adopted extinction values. Table B.1 lists the 415 QSOs and Seyfert 1 galaxies that form the sample, with positions, redshift and magnitudes, plus a cross-identification with the 1995 version of the AGN catalogue by Veron-Cetty & Veron (see Cat. <VII/215>).
- ID:
- ivo://CDS.VizieR/J/A+A/442/109
- Title:
- Hamburg/SAO Survey for ELGs. VI.
- Short Name:
- J/A+A/442/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the sixth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies. The final list resulted from follow-up spectroscopy conducted with the 4.5m MMT telescope in 1996, and with 2.2m CAHA and 6m SAO telescopes in 2000 to 2003. The data of this snap-shot spectroscopy survey confirmed 134 emission-line objects out of 182 observed candidates and allowed their quantitative spectral classification and redshift determination. We classify 73 emission-line objects as definite or probable blue compact or HII galaxies (BCG), 8 as QSOs, 4 as Seyfert 1 and 2 galaxies. 30 low-excitation objects were classified as definite or probable starburst nuclei (SBN), 3 as dwarf amorphous nuclei starburst galaxies (DANS) and 2 as LINERs. Due to the low signal-to-noise ratio we could not classify 14 ELGs (NON). For another 9 galaxies we did not detect any significant emission lines. For 98 emission-line galaxies, the redshifts and/or line intensities are determined for the first time. For the remaining 28 previously-known ELGs we give either improved data the line intensities or some independent measurements. The detection rate of ELGs is ~70%. This paper completes the classification of strong-lined ELGs found in the zone of the Hamburg/SAO survey. Together with previously known BCG/HII galaxies in this zone, this sample of ~500 objects is the largest to date in a well bound region.
- ID:
- ivo://CDS.VizieR/J/ApJS/217/5
- Title:
- HAQ survey: red QSO candidates follow-up
- Short Name:
- J/ApJS/217/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Quasi-stellar objects (QSOs) whose spectral energy distributions (SEDs) are reddened by dust either in their host galaxies or in intervening absorber galaxies are to a large degree missed by optical color selection criteria like the ones used by the Sloan Digital Sky Survey (SDSS). To overcome this bias against red QSOs, we employ a combined optical and near-infrared (near-IR) color selection. In this paper, we present a spectroscopic follow-up campaign of a sample of red candidate QSOs which were selected from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). The spectroscopic data and SDSS/UKIDSS photometry are supplemented by mid-infrared photometry from the Wide-field Infrared Survey Explorer. In our sample of 159 candidates, 154 (97%) are confirmed to be QSOs. We use a statistical algorithm to identify sightlines with plausible intervening absorption systems and identify nine such cases assuming dust in the absorber similar to Large Magellanic Cloud sightlines. We find absorption systems toward 30 QSOs, 2 of which are consistent with the best-fit absorber redshift from the statistical modeling. Furthermore, we observe a broad range in SED properties of the QSOs as probed by the rest-frame 2{mu}m flux. We find QSOs with a strong excess as well as QSOs with a large deficit at rest-frame 2{mu}m relative to a QSO template. Potential solutions to these discrepancies are discussed. Overall, our study demonstrates the high efficiency of the optical/near-IR selection of red QSOs.
- ID:
- ivo://CDS.VizieR/J/A+A/466/823
- Title:
- Hard 2-10kev X-ray selected sources
- Short Name:
- J/A+A/466/823
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Chandra and Spitzer data for the 186, extragalactic, hard 2-10keV X-ray selected sources, which lie in the central part of the Chandra Deep Field South (CDFS). For the vast majority of sources (99.5%), there is a spectroscopic or photometric redshift available. We classify 17 sources as X-ray obscured QSOs, strictly according to X-ray criteria, i.e. defined as having large hydrogen column densities (NH>10^22cm^-2^) and luminosities (LX>10^44^erg/s). The surface density of X-ray obscured QSOs is ~210{deg}^-2^. We find 18 candidate Compton-thick NH>10^24^cm^-2^ sources, of which three have QSO luminosities (LX>10^44^erg/s). The X-ray obscured QSO comprise a mixed bag of objects, covering the redshift range z=1.3-4.3. Eight of these show narrow-line optical spectra, two show no obscuration in their optical spectra that present broad lines, while for the other seven there is only a photometric redshift available. About half of the X-ray obscured QSOs show high X-ray to optical flux ratios, X/O>1, and red colours, I-3.6{mu}m>4. Combining the X-ray with the mid-IR 8{mu}m or 24{mu}m flux can be used as an additional diagnostic to sift out the heavily obscured AGN. All X-ray selected QSOs present red mid-IR colours and can be easily separated among mid-IR sources, demonstrating that mid-IR selection provides a powerful tool for detecting obscured QSOs.
- ID:
- ivo://CDS.VizieR/J/ApJS/207/19
- Title:
- Hard X-ray survey from Swift-BAT 2004-2010
- Short Name:
- J/ApJS/207/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalog of sources detected in 70 months of observations with the Burst Alert Telescope (BAT) hard X-ray detector on the Swift gamma-ray burst observatory. The Swift-BAT 70 month survey has detected 1171 hard X-ray sources (more than twice as many sources as the previous 22 month survey) in the 14-195 keV band down to a significance level of 4.8{sigma}, associated with 1210 counterparts. The 70 month Swift-BAT survey is the most sensitive and uniform hard X-ray all-sky survey and reaches a flux level of 1.03x10^-11^erg/s/cm2 over 50% of the sky and 1.34x10^-11^erg/s/cm2 over 90% of the sky. The majority of new sources in the 70 month survey continue to be active galactic nuclei, with over 700 in the catalog.
- ID:
- ivo://CDS.VizieR/J/ApJS/186/378
- Title:
- Hard X-ray survey from Swift-BAT 2004-2006
- Short Name:
- J/ApJS/186/378
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalog of sources detected in the first 22 months of data from the hard X-ray survey (14-195keV) conducted with the Burst Alert Telescope (BAT) coded mask imager on the Swift satellite. The catalog contains 461 sources detected above the 4.8{sigma} level with BAT. High angular resolution X-ray data for every source from Swift-XRT or archival data have allowed associations to be made with known counterparts in other wavelength bands for over 97% of the detections, including the discovery of ~30 galaxies previously unknown as active galactic nuclei and several new Galactic sources. A total of 266 of the sources are associated with Seyfert galaxies (median redshift z~0.03) or blazars, with the majority of the remaining sources associated with X-ray binaries in our Galaxy. This ongoing survey is the first uniform all-sky hard X-ray survey since HEAO-1 in 1977 (Fishman G.J., 1977IAUC.3134....1F). Since the publication of the nine-month BAT survey (Tueller, 2008, Cat. <J/ApJ/681/113>) we have increased the number of energy channels from four to eight and have substantially increased the number of sources with accurate average spectra. The BAT 22 month catalog is the product of the most sensitive all-sky survey in the hard X-ray band, with a detection sensitivity (4.8{sigma}) of 2.2x10^-11^erg/cm^2^/s (1mCrab) over most of the sky in the 14-195keV band.
- ID:
- ivo://CDS.VizieR/J/ApJ/749/65
- Title:
- H-ATLAS search for strongly lensed galaxies
- Short Name:
- J/ApJ/749/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- While the selection of strongly lensed galaxies (SLGs) with 500{mu}m flux density S_500_>100mJy has proven to be rather straightforward, for many applications it is important to analyze samples larger than the ones obtained when confining ourselves to such a bright limit. Moreover, only by probing to fainter flux densities is it possible to exploit strong lensing to investigate the bulk of the high-z star-forming galaxy population. We describe HALOS (the Herschel-ATLAS Lensed Objects Selection), a method for efficiently selecting fainter candidate SLGs, reaching a surface density of =~1.5-2/deg^2^, i.e., a factor of about 4-6 higher than that at the 100mJy flux limit. HALOS will allow the selection of up to ~1000 candidate SLGs (with amplifications {mu}>~2) over the full H-ATLAS survey area. Applying HALOS to the H-ATLAS Science Demonstration Phase field (=~14.4deg^2^) we find 31 candidate SLGs, whose candidate lenses are identified in the VIKING near-infrared catalog. Using the available information on candidate sources and candidate lenses we tentatively estimate a =~72% purity of the sample. As expected, the purity decreases with decreasing flux density of the sources and with increasing angular separation between candidate sources and lenses. The redshift distribution of the candidate lensed sources is close to that reported for most previous surveys for lensed galaxies, while that of candidate lenses extends to redshifts substantially higher than found in the other surveys. The counts of candidate SLGs are also in good agreement with model predictions. Even though a key ingredient of the method is the deep near-infrared VIKING photometry, we show that H-ATLAS data alone allow the selection of a similarly deep sample of candidate SLGs with an efficiency close to 50%; a slightly lower surface density (=~ 1.45/deg2) can be reached with a ~70% efficiency.
- ID:
- ivo://CDS.VizieR/J/AJ/127/3137
- Title:
- Hawaii redshifts in the ACS-GOODS region
- Short Name:
- J/AJ/127/3137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of an extensive spectroscopic survey of galaxies in the roughly 160 arcmin^2^ ACS-GOODS region surrounding the Hubble Deep Field North (HDF-N). We have identified 892 galaxies or stars with z<24, R<24.5, or B<25 in the region. The spectra were obtained with either the DEIMOS or LRIS spectrographs on the Keck 10m telescopes. The results are compared with photometric redshift estimates and with redshifts from the literature, as well as with the redshifts of a parallel effort led by a group at Keck. Our sample, when combined with the literature data, provides identifications for 1324 sources. We use our results to determine the redshift distributions with magnitude, to analyze the rest-frame color distributions with redshift and spectral type, and to investigate the dependence of the X-ray galaxy properties on the local galaxy density in the redshift interval z=0-1.5. We find the rather surprising result that the galaxy X-ray properties are not strongly dependent on the local galaxy density for galaxies in the same luminosity range.
- ID:
- ivo://CDS.VizieR/J/ApJ/796/64
- Title:
- H{beta} and Ly{alpha} emitting galaxies at z~2
- Short Name:
- J/ApJ/796/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the H{beta} line strengths of 1.90<z<2.35 star-forming galaxies observed with the near-IR grism of the Hubble Space Telescope with ground-based measurements of Ly{alpha} from the HETDEX Pilot Survey and narrow-band imaging. By examining the line ratios of 73 galaxies, we show that most star-forming systems at this epoch have a Ly{alpha} escape fraction below ~6%.