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961. LAE galaxies in the ECDF-S at z~2.1 and z~3.1
ID:
ivo://CDS.VizieR/J/ApJ/753/95
Title:
LAE galaxies in the ECDF-S at z~2.1 and z~3.1
Short Name:
J/ApJ/753/95
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a rest-frame ultraviolet morphological analysis of 108 z~2.1 Ly{alpha} emitters (LAEs) in the Extended Chandra Deep Field South and compare it to a similar sample of 171 LAEs at z~3.1. Using Hubble Space Telescope images from the Galaxy Evolution from Morphology and SEDs survey, Great Observatories Origins Deep Survey, and Hubble Ultradeep Field, we measure size and photometric component distributions, where photometric components are defined as distinct clumps of UV-continuum emission. At both redshifts, >80% of LAEs have observed half-light radii <2kpc, but the median half-light radius rises from 0.95+/-0.04kpc at z=3.1 to 1.41+/-0.14kpc at z=2.1. A similar evolution is seen in the sizes of individual rest-UV components, but there is no evidence for evolution in the number of multi-component systems. In the z=2.1 sample, we see clear correlations between the size of an LAE and other physical properties derived from its spectral energy distribution (SED). LAEs are found to be larger for galaxies with higher stellar mass, star formation rate, and dust obscuration, but there is no evidence for a trend between equivalent width and half-light radius at either redshift. The presence of these correlations suggests that a wide range of objects are being selected by LAE surveys at z~2, including a significant fraction of objects for which a massive and moderately extended population of old stars underlies the young starburst giving rise to the Ly{alpha} emission.
962. LAEs at z~4.5 in the LALA Cetus field
ID:
ivo://CDS.VizieR/J/ApJ/706/762
Title:
LAEs at z~4.5 in the LALA Cetus field
Short Name:
J/ApJ/706/762
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a large sample of Ly{alpha}-emitting galaxies (LAEs) spectroscopically confirmed at redshift z~4.5, based on Inamori-Magellan Areal Camera and Spectrograph spectroscopic observations of candidate z~4.5 Ly{alpha}-emitting galaxies in the large area Lyman alpha (LALA) narrowband imaging survey Cetus field. We identify 110 of them as z~4.5 Ly{alpha} emitters based on single-line detections with no continuum emission blueward of the line. Six foreground galaxies are identified, either based on multiple lines or blueward continuum emission. The Ly{alpha} confirmation rate varies from <50% to 76% for candidates selected in different narrowband filters at slightly different redshifts. The sample includes many objects with equivalent widths (EWs)>~200{AA}. These large EW candidates are spectroscopically confirmed at the same rate as candidates with more modest EWs.
963. Lag measurements for 15 z<0.8 QSOs from the SDSS-RM
ID:
ivo://CDS.VizieR/J/ApJ/818/30
Title:
Lag measurements for 15 z<0.8 QSOs from the SDSS-RM
Short Name:
J/ApJ/818/30
Date:
21 Oct 2021
Publisher:
CDS
Description:
Reverberation mapping (RM) measurements of broad-line region (BLR) lags in z>0.3 quasars are important for directly measuring black hole masses in these distant objects, but so far there have been limited attempts and success given the practical difficulties of RM in this regime. Here we report preliminary results of 15 BLR lag measurements from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project, a dedicated RM program with multi-object spectroscopy designed for RM over a wide redshift range. The lags are based on the 2014 spectroscopic light curves alone (32 epochs over six months) and focus on the H{beta} and Mg II broad lines in the 100 lowest-redshift (z<0.8) quasars included in SDSS-RM; they represent a small subset of the lags that SDSS-RM (including 849 quasars to z~4.5) is expected to deliver. The reported preliminary lag measurements are for intermediate-luminosity quasars at 0.3<~z<0.8, including nine H{beta} lags and six Mg II lags, for the first time extending RM results to this redshift-luminosity regime and providing direct quasar black hole mass estimates over approximately half of cosmic time. The Mg II lags also increase the number of known Mg II lags by several fold and start to explore the utility of Mg II for RM at high redshift. The location of these new lags at higher redshifts on the observed BLR size-luminosity relationship is statistically consistent with previous H{beta} results at z<0.3. However, an independent constraint on the relationship slope at z>0.3 is not yet possible owing to the limitations in our current sample. Our results demonstrate the general feasibility and potential of multi-object RM for z>0.3 quasars.
964. LALA Bootes field X-ray source catalog
ID:
ivo://CDS.VizieR/J/AJ/127/213
Title:
LALA Bootes field X-ray source catalog
Short Name:
J/AJ/127/213
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of a deep, 172ks Chandra observation of the Large Area Lyman Alpha survey (LALA) Bootes field, obtained with the Advanced CCD Imaging Spectrometer (ACIS-I) on board the Chandra X-Ray Observatory. This is one of the deepest Chandra images of the extragalactic sky; only the 2Ms Chandra Deep Field North (CDF-N) and 1Ms Chandra Deep Field South (CDF-S) are substantially deeper. In this paper we present the X-ray source catalog obtained from this image, along with an analysis of source counts and optical identifications. The X-ray image is composed of two individual observations obtained in 2002 and reaches 0.5-2.0 and 2.0-10.0keV flux limits of 1.5x10^-16^ and 1.0x10^-15^ergs/cm^2^/s, respectively, for point sources near the aim point. A total of 168 X-ray sources were detected: 160 in the 0.5-7.0keV band, 132 in the 0.5-2.0keV band, and 111 in the 2.0-7.0keV band. Our primary optical data are R-band imaging from the NOAO Deep Wide-Field Survey (NDWFS), with a limiting magnitude of R=25.7 (Vega, 3{sigma}, and 4" diameter aperture).
965. LAMOST DR4 catalogs
ID:
ivo://CDS.VizieR/V/153
Title:
LAMOST DR4 catalogs
Short Name:
V/153
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is a Chinese national scientific research facility operated by the National Astronomical Observatories, Chinese Academy of Sciences. It is a special reflecting Schmidt telescope with 4000 fibers in a field of view of 20 deg22in the sky. Until July 2016, LAMOST has completed its pilot survey which was launched in October 2011 and ended in June 2012, and the first four years of regular survey which was initiated on September 2012. After this five-year-survey, we totally obtain 7,617,035 spectra, which consist of stars, galaxies, quasars and other unknown objects. Now, the fourth data release (DR4) has published online (http://dr4.lamost.org/), and released data products include 1. Spectra. - In general, there are 7,617,035 flux- and wavelength-calibrated, sky-subtracted spectra in DR4, including 6,943,865 stars, 117,254 galaxies, 36,575 quasars, and 519,341 unknown objects, and these spectra cover the wavelength range of 3690-9100 angstrom with a resolution of 1800 at the 5500 angstrom. 2. Spectroscopic Parameters Catalogs. - In this data release, six spectroscopic parameters catalogs are also published, they are the LAMOST general catalog, the A, F, G and K type star catalog, the A type star catalog, the M dwarf catalog, the observed plate information catalog, and the input catalog respectively. For the first four catalogs, they all include 36 columns of basic spectroscopic information, for example, right ascension, declination, signal to noise ratio, magnitude, classification and redshift. Also, the A type star catalog publish line indices of six spectral lines and four balmer line widths at 20% below the local continua, the A, F, G and K type star catalog provides effective temperature, surface gravity, and metallicity, and the M dwarf catalog releases the equivalent width of Halpha line, ten line indices, one metallicity sensitive parameter and a flag that indicates whether or not exist magnetic activity. For the observed plate information catalog, it mainly contains nine basic plate information for all published plates. At last, the input catalog includes 24 basic fields mentioned above, and three new fields which are not included in the above catalogs.
966. LAMOST DR2 catalogs
ID:
ivo://CDS.VizieR/V/149
Title:
LAMOST DR2 catalogs
Short Name:
V/149
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs.
967. LAMOST DR5 catalogs
ID:
ivo://CDS.VizieR/V/164
Title:
LAMOST DR5 catalogs
Short Name:
V/164
Date:
22 Feb 2022
Publisher:
CDS
Description:
We totally published 9,026,365 targets in this table, including 8,183,160 stars, 152,863 galaxies, 52,453 quasars, and 637,889 unknown objects. In addition, there are 5,808,985 objects with g band S/Ns larger than 10, 7,701,235 objects with i band S/Ns larger than 10, and 5,734,239 objects with g band S/Ns larger than 10 and i band S/Ns larger than 10. On the website http://dr5.lamost.org/catalogue, we provide two format LAMOST general catalogs, which include a FITS table and a CSV table, and the two catalog files have the same contents.
968. LAMOST DR1 catalogs
ID:
ivo://CDS.VizieR/V/146
Title:
LAMOST DR1 catalogs
Short Name:
V/146
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs. Objects in both the pilot survey and the first year regular survey are included in the LAMOST DR1. The pilot survey started in October 2011 and ended in June 2012, and the data have been released to the public as the LAMOST Pilot Data Release in August 2012. The regular survey started in September 2012, and completed its first year of operation in June 2013. The LAMOST DR1 includes a total of 1202 plates containing 2955336 spectra, of which 1790879 spectra have observed signal-to-noise ratio (SNR)>=10. All data with SNR>=2 are formally released as LAMOST DR1 under the LAMOST data policy. This data release contains a total of 2204696 spectra, of which 1944329 are stellar spectra, 12082 are galaxy spectra and 5017 are quasars. The DR1 not only includes spectra, but also three stellar catalogs with measured parameters: late A,FGK-type stars with high quality spectra (1061918 entries), A-type stars (100073 entries), and M-type stars (121522 entries). This paper introduces the survey design, the observational and instrumental limitations, data reduction and analysis, and some caveats. A description of the FITS structure of spectral files and parameter catalogs is also provided.
969. LAMOST DR2 star clusters candidate members
ID:
ivo://CDS.VizieR/J/other/RAA/15.1197
Title:
LAMOST DR2 star clusters candidate members
Short Name:
J/other/RAA/15.1
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this work, we provide 2189 photometrically- and kinematically-selected candidate members of 24 star clusters from the LAMOST DR2 catalog. We perform two-step membership identification: selection along the stellar track in the color-magnitude diagram, i.e., photometric identification, and selection from the distribution of radial velocities, i.e. the kinematic identification. We find that the radial velocities from the LAMOST data are very helpful in the membership identification. The mean probability of membership is 40% for the sample selected with radial velocity. With these 24 star clusters, we investigate the performance of the radial velocity and metallicity estimated with the LAMOST pipeline. We find that the systematic offsets in radial velocity and metallicity are 0.85+/-1.26km/s and -0.08+/-0.04dex, with dispersions of 5.47^+1.16^_-0.71_km/s and 0.13^+0.04^_-0.02_dex, respectively. Finally, we propose that the photometrically-selected candidate members of the clusters covered by the LAMOST footprint should be assigned higher priority so that more candidate stars can be observed.
970. LAMOST DR2 white dwarfs
ID:
ivo://CDS.VizieR/J/MNRAS/454/2787
Title:
LAMOST DR2 white dwarfs
Short Name:
J/MNRAS/454/2787
Date:
21 Oct 2021
Publisher:
CDS
Description:
Here we present a catalogue of 1056 spectroscopically identified hydrogen-dominated white dwarfs (DAWDs), 34 helium-dominated white dwarfs (DBWDs) and 276 white dwarf main sequence (WDMS) binaries from the Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey data release 2 (DR2). 383 DAWDs, 4 DBWDs and 138 WDMSs are new identifications after cross-match with literature. There are ~4100k spectra in total from DR 2. The low ratio of white dwarfs found in LAMOST is attributed to biased selection of LAMOST input catalogue and much brighter targets relative to stars observed in Sloan Digital Sky Survey. In this paper, a new DAWD selection method is adopted as a new attempt and supplement to the traditional methods. The effective temperature, surface gravity, mass, cooling age and distance of high signal-to-noise DAWDs are estimated. The peak of the mass distribution is found to be ~0.6M_{sun}_, which is consistent with previous work. The parameters of WDMS binaries are also provided in this paper. As the foundation of our future work, which is to identify more WDs with debris disc, WDs found in LAMOST showed a lot of potential. Interesting infrared-excess WDs will be reported in our forthcoming paper.