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441. Dark molecular gas in the Galaxy II. Perseus arm
ID:
ivo://CDS.VizieR/J/ApJ/883/158
Title:
Dark molecular gas in the Galaxy II. Perseus arm
Short Name:
J/ApJ/883/158
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results from a new, highly sensitive ({Delta}T_mb_~3mK) survey for thermal OH emission at 1665 and 1667MHz over a dense, 9x9pix grid covering a 1{deg}x1{deg} patch of sky in the direction of l=105.00{deg}, b=+2.50{deg} toward the Perseus spiral arm of our Galaxy. We compare our Green Bank Telescope 1667MHz OH results with archival ^12^CO(1-0) observations from the Five College Radio Astronomy Observatory Outer Galaxy Survey within the velocity range of the Perseus Arm at these galactic coordinates. Out of the 81 statistically independent pointings in our survey area, 86% show detectable OH emission at 1667MHz, and 19% of them show detectable CO emission. We explore the possible physical conditions of the observed features using a set of diffuse molecular cloud models. In the context of these models, both OH and CO disappear at current sensitivity limits below an A_v_ of 0.2, but the CO emission does not appear until the volume density exceeds 100-200cm^-3^. These results demonstrate that a combination of low column density A_v_ and low volume density n_H_ can explain the lack of CO emission along sight lines exhibiting OH emission. The 18cm OH main lines, with their low critical density of n*~1cm^-3^, are collisionally excited over a large fraction of the quiescent galactic environment and, for observations of sufficient sensitivity, provide an optically thin radio tracer for diffuse H_2_.
442. DB white dwarfs with SDSS and Gaia data
ID:
ivo://CDS.VizieR/J/ApJ/882/106
Title:
DB white dwarfs with SDSS and Gaia data
Short Name:
J/ApJ/882/106
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a comprehensive analysis of DB white dwarfs drawn from the Sloan Digital Sky Survey, based on model fits to ugriz photometry and medium-resolution spectroscopy from the Sloan Digital Sky Survey. We also take advantage of the exquisite trigonometric parallax measurements recently obtained by the Gaia mission. Using the so-called photometric and spectroscopic techniques, we measure the atmospheric and physical parameters of each object in our sample (Teff, logg, H/He, Ca/He, R, M), and compare the values obtained from both techniques in order to assess the precision and accuracy of each method. We then explore in great detail the surface gravity, stellar mass, and hydrogen abundance distributions of DB white dwarfs as a function of effective temperature. We present some clear evidence for a large population of unresolved double-degenerate binaries composed of DB+DB and even DB+DA white dwarfs. In the light of our results, we finally discuss the spectral evolution of DB white dwarfs, in particular the evolution of the DB-to-DA ratio as a function of Teff, and we revisit the question of the origin of hydrogen in DBA white dwarfs.
443. Deep ATLAS radio observations of CDFS
ID:
ivo://CDS.VizieR/J/AJ/132/2409
Title:
Deep ATLAS radio observations of CDFS
Short Name:
J/AJ/132/2409
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first results from the Australia Telescope Large Area Survey, which consists of deep radio observations of a 3.7deg^2^ field surrounding the Chandra Deep Field-South, largely coincident with the infrared Spitzer Wide-Area Infrared Extragalactic (SWIRE) Survey. We also list cross-identifications to infrared and optical photometry data from SWIRE, and ground-based optical spectroscopy. A total of 784 radio components are identified, corresponding to 726 distinct radio sources, nearly all of which are identified with SWIRE sources. Of the radio sources with measured redshifts, most lie in the redshift range 0.5-2 and include both star-forming galaxies and active galactic nuclei. We identify a rare population of infrared-faint radio sources that are bright at radio wavelengths but are not seen in the available optical, infrared, or X-ray data. Such rare classes of sources can only be discovered in wide, deep surveys such as this.
444. Deep Chandra survey of the Groth Strip
ID:
ivo://CDS.VizieR/J/MNRAS/356/568
Title:
Deep Chandra survey of the Groth Strip
Short Name:
J/MNRAS/356/568
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a 200-ks Chandra observation of part of the Groth Strip region, using the ACIS-I instrument. We present a relatively simple method for the detection of point sources and calculation of limiting sensitivities, which we argue is at least as sensitive and more self-consistent than previous methods presented in the literature. A total of 158 distinct X-ray sources are included in our point-source catalogue in the ACIS-I area. The number counts show a relative dearth of X-ray sources in this region.
445. Deep Chandra survey of the Groth Strip. II.
ID:
ivo://CDS.VizieR/J/MNRAS/371/221
Title:
Deep Chandra survey of the Groth Strip. II.
Short Name:
J/MNRAS/371/221
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper, we discuss the optical and X-ray spectral properties of the sources detected in a single 200-ks Chandra pointing in the Groth-Westphal Strip region. A wealth of optical photometric and spectroscopic data are available in this field providing optical identifications and redshift determinations for the X-ray population. The optical photometry and spectroscopy used here are primarily from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) survey with additional redshifts obtained from the literature. These are complemented with the deeper (r>>26mag) multiwaveband data (ugriz) from the Canada-France-Hawaii Telescope Legacy Survey to estimate photometric redshifts and to optically identify sources fainter than the DEEP2 magnitude limit (R_AB_>>24.5mag). We focus our study on the 2-10keV selected sample comprising 97 sources to the limit 8x10^-16^erg/s/cm^2^, this being the most complete in terms of optical identification rate (86 per cent) and redshift determination fraction (63 per cent; both spectroscopic and photometric).
446. Deep Chandra survey of the SMC. III. HMXBs
ID:
ivo://CDS.VizieR/J/ApJ/887/20
Title:
Deep Chandra survey of the SMC. III. HMXBs
Short Name:
J/ApJ/887/20
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have compiled the most complete census of high-mass X-ray binaries (HMXBs) in the Small Magellanic Cloud with the aim to investigate the formation efficiency of young accreting binaries in its low-metallicity environment. In total, we use 123 X-ray sources with detections in our Chandra X-ray Visionary Program (XVP), supplemented by 14 additional (likely and confirmed) HMXBs identified by Haberl & Sturm (2016, J/A+A/586/A81) that fall within the XVP area, but are neither detected in our survey (nine sources) nor matched with any of the 127 sources identified in the XVP data (five sources). Specifically, we examine the number ratio of the HMXBs [N(HMXBs)] to (a) the number of OB stars, (b) the local star formation rate (SFR), and (c) the stellar mass produced during the specific star formation burst, all as a function of the age of their parent stellar populations. Each of these indicators serves a different role, but in all cases we find that the HMXB formation efficiency increases as a function of time (following a burst of star formation) up to ~40-60Myr, and then gradually decreases. The formation efficiency peaks at ~30-40Myr with average rates of N(HMXB)/SFR=339_-83_^+78^(M_{sun}_/yr)^-1^, and N(HMXB)/M*=(8.74_-0.92_^+1.0^)x10^-6^M_{sun}_^-1^, in good agreement with previous estimates of the average formation efficiency in the broad ~20-60Myr age range.
447. DEEP2 galaxies with UV spectra in the EGS
ID:
ivo://CDS.VizieR/J/ApJ/758/135
Title:
DEEP2 galaxies with UV spectra in the EGS
Short Name:
J/ApJ/758/135
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate galactic-scale outflowing winds in 72 star-forming galaxies at z~1 in the Extended Groth Strip. Galaxies were selected from the DEEP2 survey and follow-up LRIS spectroscopy was obtained covering Si II, C IV, Fe II, Mg II, and Mg I lines in the rest-frame ultraviolet. Using Galaxy Evolution Explorer (GALEX), Hubble Space Telescope (HST), and Spitzer imaging available for the Extended Groth Strip, we examine galaxies on a per-object basis in order to better understand both the prevalence of galactic outflows at z~1 and the star-forming and structural properties of objects experiencing outflows. Gas velocities, measured from the centroids of Fe II interstellar absorption lines, are found to span the interval [-217,+155]km/s. We find that ~40% (10%) of the sample exhibits blueshifted Fe II lines at the 1{sigma} (3{sigma}) level. We also measure maximal outflow velocities using the profiles of the Fe II and Mg II lines; we find that Mg II frequently traces higher velocity gas than Fe II. Using quantitative morphological parameters derived from the HST imaging, we find that mergers are not a prerequisite for driving outflows. More face-on galaxies also show stronger winds than highly inclined systems, consistent with the canonical picture of winds emanating perpendicular to galactic disks. In light of clumpy galaxy morphologies, we develop a new physically motivated technique for estimating areas corresponding to star formation. We use these area measurements in tandem with GALEX-derived star formation rates (SFRs) to calculate SFR surface densities. At least 70% of the sample exceeds an SFR surface density of 0.1M_{sun}_/yr/kpc2, the threshold necessary for driving an outflow in local starbursts. At the same time, the outflow detection fraction of only 40% in Fe II absorption provides further evidence for an outflow geometry that is not spherically symmetric. We see a ~3{sigma} trend between outflow velocity and SFR surface density, but no significant trend between outflow velocity and SFR. Higher resolution data are needed in order to test the scaling relations between outflow velocity and both SFR and SFR surface density predicted by theory.
448. DEEP3 Galaxy Redshift Survey: GOODS-N field
ID:
ivo://CDS.VizieR/J/ApJS/193/14
Title:
DEEP3 Galaxy Redshift Survey: GOODS-N field
Short Name:
J/ApJS/193/14
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of spectroscopic observations in the GOODS-N field completed using DEIMOS on the Keck II telescope as part of the DEEP3 Galaxy Redshift Survey (M. C. Cooper et al. 2011, in preparation). Observations of 370 unique targets down to a limiting magnitude of R_AB_=24.4 yielded 156 secure redshifts. In addition to redshift information, we provide sky-subtracted one- and two-dimensional spectra of each target. Observations were conducted following the procedures of the Team Keck Redshift Survey (TKRS, Cat. J/AJ/127/3121), thereby producing spectra that augment the TKRS sample while maintaining the uniformity of its spectral database.
449. DEEP2 Galaxy Redshift Survey: SDSS QSOs
ID:
ivo://CDS.VizieR/J/ApJ/654/115
Title:
DEEP2 Galaxy Redshift Survey: SDSS QSOs
Short Name:
J/ApJ/654/115
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the clustering of Deep Extragalactic Evolutionary Probe 2 (DEEP2) galaxies at 0.7<z<1.4 around quasars identified using both the Sloan Digital Sky Survey (SDSS) and DEEP2 surveys. We measure the two-point cross-correlation of a sample of 36 optically selected, spectroscopically identified quasars from the SDSS and 16 more found in the DEEP2 survey with the full DEEP2 galaxy sample over scales 0.1h^-1^MPc<r_p_<10h^-1^Mpc.
450. Deep 15GHz survey (9C continued)
ID:
ivo://CDS.VizieR/J/MNRAS/404/1005
Title:
Deep 15GHz survey (9C continued)
Short Name:
J/MNRAS/404/1005
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 9C survey of radio sources with the Ryle Telescope at 15.2GHz was set up to survey the fields of the cosmic microwave background telescope, the Very Small Array. In our first paper we described three regions of the survey, constituting a total area of to a completeness limit of ~25mJy. Here we present results from series of deeper regions, amounting to an area of 115deg^2^ complete to ~10mJy and of 29deg^2^ complete to ~5.5mJy. The compound source catalogue contains a total of 643 sources.

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