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1051. Lyman-continuum emission at z~3 in SSA22 field
ID:
ivo://CDS.VizieR/J/ApJ/736/18
Title:
Lyman-continuum emission at z~3 in SSA22 field
Short Name:
J/ApJ/736/18
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of an ultradeep, narrowband imaging survey for Lyman-continuum (LyC) emission at z~3 in the SSA22a field. We employ a custom narrowband filter centered at {lambda}=3640{AA} (NB3640), which probes the LyC region for galaxies at z>=3.06. We also analyze new and archival NB4980 imaging tuned to the wavelength of the Ly{alpha} emission line at z=3.09, and archival broadband B, V, and R images of the non-ionizing UV continuum. Our NB3640 images contain 26 z>=3.06 Lyman break galaxies (LBGs) as well as a set of 130 Ly{alpha} emitters (LAEs), identified by their excess NB4980 flux relative to the BV continuum. Six LBGs and 28 LAEs are detected in the NB3640 image. LBGs appear to span a range of NB3640-R colors, while LAEs appear bimodal in their NB3640-R properties. We estimate average UV-to-LyC flux density ratios.
1052. Machine-learning regression of extinction in Gaia DR2
ID:
ivo://CDS.VizieR/J/AJ/159/84
Title:
Machine-learning regression of extinction in Gaia DR2
Short Name:
J/AJ/159/84
Date:
21 Oct 2021
Publisher:
CDS
Description:
Machine learning has become a popular tool to help us make better decisions and predictions, based on experiences, observations, and analyzing patterns, within a given data set without explicit functions. In this paper, we describe an application of the supervised machine-learning algorithm to the extinction regression for the second Gaia data release, based on the combination of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, Sloan Extension for Galactic Understanding and Exploration, and the Apache Point Observatory Galactic Evolution Experiment. The derived extinction in our training sample is consistent with other spectrum-based estimates, and its standard deviation of the cross-validations is 0.0127mag. A blind test is carried out using the RAdial Velocity Experiment catalog, and the standard deviation is 0.0372mag. Such a precise training sample enables us to regress the extinction, E(BP-RP), for 133 million stars in the second Gaia data release. Of these, 106 million stars have the uncertainties less than 0.1mag, which suffer less bias from the external regression. We also find that there are high deviations between the extinctions from photometry-based methods, and between spectrum- and photometry-based methods. This implies that the spectrum-based method could bring more signal to a regressing model than multiband photometry, and a higher signal-to-noise ratio would acquire a more reliable result.
1053. MACHO Galactic Bulge microlensing events
ID:
ivo://CDS.VizieR/J/ApJ/631/906
Title:
MACHO Galactic Bulge microlensing events
Short Name:
J/ApJ/631/906
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 450 relatively high signal-to-noise ratio microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout our fields, and as expected, they show a clear concentration toward the Galactic center. No optical depth is given for this sample, since no blending efficiency calculation has been performed and we find evidence for substantial blending. In a companion paper we give optical depths for the subsample of events on clump giant source stars, where blending is a less significant effect. Several events with sources that may belong to the Sagittarius dwarf galaxy are identified. For these events even relatively low dispersion spectra could suffice to classify these events as either consistent with Sagittarius membership or as non-Sagittarius sources. Several unusual events, such as microlensing of periodic variable source stars, binary lens events, and an event showing extended source effects, are identified. We also identify a number of contaminating background events as cataclysmic variable stars.
1054. MACT survey. I. Opt. spectroscopy in Subaru Deep Field
ID:
ivo://CDS.VizieR/J/ApJS/226/5
Title:
MACT survey. I. Opt. spectroscopy in Subaru Deep Field
Short Name:
J/ApJS/226/5
Date:
21 Oct 2021
Publisher:
CDS
Description:
Deep rest-frame optical spectroscopy is critical for characterizing and understanding the physical conditions and properties of the ionized gas in galaxies. Here, we present a new spectroscopic survey called "Metal Abundances across Cosmic Time" or MACT, which will obtain rest-frame optical spectra for ~3000 emission-line galaxies. This paper describes the optical spectroscopy that has been conducted with MMT/Hectospec and Keck/DEIMOS for ~1900 z=0.1-1 emission-line galaxies selected from our narrowband and intermediate-band imaging in the Subaru Deep Field. In addition, we present a sample of 164 galaxies for which we have measured the weak [OIII]{lambda}4363 line (66 with at least 3{sigma} detections and 98 with significant upper limits). This nebular emission line determines the gas-phase metallicity by measuring the electron temperature of the ionized gas. This paper presents the optical spectra, emission-line measurements, interstellar properties (e.g., metallicity, gas density), and stellar properties (e.g., star formation rates, stellar mass). Paper II of the MACT survey (Ly et al. 2016ApJ...828...67L) presents the first results on the stellar mass-gas metallicity relation at z<=1 using the sample with [OIII]{lambda}4363 measurements.
1055. MaDCoWS. I. Catalog of z~1 galaxy clusters
ID:
ivo://CDS.VizieR/J/ApJS/240/33
Title:
MaDCoWS. I. Catalog of z~1 galaxy clusters
Short Name:
J/ApJS/240/33
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the Massive and Distant Clusters of WISE Survey (MaDCoWS), a search for galaxy clusters at 0.7<=z<=1.5 based upon data from the Wide-field Infrared Survey Explorer (WISE) mission. MaDCoWS is the first cluster survey capable of discovering massive clusters at these redshifts over the full extragalactic sky. The search is divided into two regions-the region of the extragalactic sky covered by Pan-STARRS ({delta}{>}-30{deg}) and the remainder of the southern extragalactic sky at {delta}{<}-30{deg} for which shallower optical data from the SuperCOSMOS Sky Survey is available. In this paper, we describe the search algorithm, characterize the sample, and present the first MaDCoWS data release-catalogs of the 2433 highest amplitude detections in the WISE-Pan-STARRS region and the 250 highest amplitude detections in the WISE-SuperCOSMOS region. A total of 1723 of the detections from the WISE-Pan-STARRS sample have also been observed with the Spitzer Space Telescope, providing photometric redshifts and richnesses, and an additional 64 detections within the WISE-SuperCOSMOS region also have photometric redshifts and richnesses. Spectroscopic redshifts for 38 MaDCoWS clusters with IRAC photometry demonstrate that the photometric redshifts have an uncertainty of {sigma}z/(1+z)~0.036. Combining the richness measurements with Sunyaev-Zel'dovich observations of MaDCoWS clusters, we also present a preliminary mass-richness relation that can be used to infer the approximate mass distribution of the full sample. The estimated median mass for the WISE-Pan-STARRS catalog is M_500_=1.6_-0.8_^+0.7^x10^14^M_{sun}_, with the Sunyaev-Zel'dovich data confirming that we detect clusters with masses up to M_500_~5x10^14^M_{sun}_ (_M200_~10^15^M_{sun}_).
1056. Magellanic Clouds Photometric Survey: the LMC
ID:
ivo://CDS.VizieR/J/AJ/128/1606
Title:
Magellanic Clouds Photometric Survey: the LMC
Short Name:
J/AJ/128/1606
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present our catalog of U, B, V, and I stellar photometry of the central 64deg^2^ area of the Large Magellanic Cloud. Internal and external astrometric and photometric tests using existing optical photometry (U, B, and V from Massey's bright star catalog (Cat. <II/236>) and I from the near-infrared sky survey DENIS) are used to confirm our observational uncertainty estimates. We fit stellar atmosphere models to the optical data to check the consistency of the photometry for individual stars across the passbands and to estimate the line-of-sight extinction. Finally, we use the estimated line-of-sight extinctions to produce an extinction map across the Large Magellanic Cloud, confirm the variation of extinction as a function of stellar population, and produce a simple geometric model for the extinction as a function of stellar population.
1057. Magellanic Quasars Survey. II. AGNs behind LMC
ID:
ivo://CDS.VizieR/J/ApJ/746/27
Title:
Magellanic Quasars Survey. II. AGNs behind LMC
Short Name:
J/ApJ/746/27
Date:
21 Oct 2021
Publisher:
CDS
Description:
We quadruple the number of quasars known behind the Large Magellanic Cloud (LMC) from 56 (42 in the Optical Gravitational Lensing Experiment (OGLE)-III LMC fields) to 200 by spectroscopically confirming 169 (144 new) quasars from a sample of 845 observed candidates in four ~3 deg^2^ Anglo-Australian Telescope/AAOmega fields south of the LMC center. The candidates were selected based on their Spitzer mid-infrared colors, X-ray emission, and/or optical variability properties in the database of the OGLE microlensing survey. The contaminating sources can be divided into 115 young stellar objects (YSOs), 17 planetary nebulae (PNe), 39 Be and 24 blue stars, 68 red stars, and 12 objects classed as either YSO/PN or blue star/YSO. There are also 402 targets with either featureless spectra or too low signal-to-noise ratios for source classification. Our quasar sample is 50% (30%) complete at I = 18.6 mag (19.3 mag). The newly discovered active galactic nuclei (AGNs) provide many additional reference points for proper motion studies of the LMC, and the sample includes 10 bright AGNs (I < 18 mag) that are potentially suitable for absorption line studies. Their primary use, however, is for detailed studies of quasar variability, as they all have long-term, high cadence, continuously growing light curves from the microlensing surveys of the LMC. Completing the existing Magellanic Quasars Survey fields in the LMC and Small Magellanic Cloud should yield a sample of ~700 well-monitored AGNs, and expanding it to the larger regions covered by the OGLE-IV survey should yield a sample of ~3600 AGNs.
1058. Magellan/IMACS spectra of Crater II & Hercules
ID:
ivo://CDS.VizieR/J/ApJ/883/11
Title:
Magellan/IMACS spectra of Crater II & Hercules
Short Name:
J/ApJ/883/11
Date:
21 Jan 2022 09:25:05
Publisher:
CDS
Description:
We investigate the possibility that the dwarf galaxies Crater II and Hercules have previously been tidally stripped by the Milky Way. We present Magellan/IMACS spectra of candidate member stars in both objects. We identify 37 members of Crater II, 25 of which have velocity measurements in the literature, and we classify three stars within that subset as possible binaries. We find that including or removing these binary candidates does not change the derived velocity dispersion of Crater II. Excluding the binary candidates, we measure a velocity dispersion of {sigma}_Vlos_=2.7_-0.4_^+0.5^km/s, corresponding to M/L=47_-13_^+17^M_{sun}_/L_{sun}_. We measure a mean metallicity of [Fe/H]=-1.95_-0.05_^+0.06^, with a dispersion of {sigma}_[Fe/H]_=0.18_-0.08_^+0.06^. Our velocity dispersion and metallicity measurements agree with previous measurements for Crater II, and confirm that the galaxy resides in a kinematically cold dark-matter halo. We also search for spectroscopic members stripped from Hercules in the possible extratidal stellar overdensities surrounding the dwarf. For both galaxies, we calculate proper motions using Gaia DR2 astrometry, and use their full 6D phase space information to evaluate the probability that their orbits approach sufficiently close to the Milky Way to experience tidal stripping. Given the available kinematic data, we find a probability of ~40% that Hercules has suffered tidal stripping. The proper motion of Crater II makes it almost certain to be stripped.
1059. MAGPIS 20cm survey
ID:
ivo://CDS.VizieR/J/AJ/131/2525
Title:
MAGPIS 20cm survey
Short Name:
J/AJ/131/2525
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the Multi-Array Galactic Plane Imaging Survey (MAGPIS), which maps portions of the first Galactic quadrant with an angular resolution, sensitivity, and dynamic range that surpass existing radio images of the Milky Way by more than an order of magnitude. The source detection threshold at 20cm is in the range 12mJy over the 85% of the survey region (5{deg}<l<32{deg}, |b|<0.8{deg}) not covered by bright extended emission; the angular resolution is ~6". We catalog over 3000 discrete sources (diameters mostly <30") and present an atlas of ~400 diffuse emission regions. New and archival data at 90cm for the whole survey area are also presented. Comparison of our catalogs and images with the Midcourse Space Experiment mid-infrared data allows us to provide preliminary discrimination between thermal and nonthermal sources. We identify 49 high-probability supernova remnant candidates, increasing by a factor of 7 the number of known remnants with diameters smaller than 5' in the survey region; several are pulsar wind nebula candidates and/or very small diameter remnants (D<45").
1060. Main Belt asteroids with WISE/NEOWISE. I.
ID:
ivo://CDS.VizieR/J/ApJ/741/68
Title:
Main Belt asteroids with WISE/NEOWISE. I.
Short Name:
J/ApJ/741/68
Date:
01 Feb 2022 07:05:56
Publisher:
CDS
Description:
We present initial results from the Wide-field Infrared Survey Explorer (WISE), a four-band all-sky thermal infrared survey that produces data well suited for measuring the physical properties of asteroids, and the NEOWISE enhancement to the WISE mission allowing for detailed study of solar system objects. Using a NEATM thermal model fitting routine, we compute diameters for over 100000 Main Belt asteroids (MBAs) from their IR thermal flux, with errors better than 10%. We then incorporate literature values of visible measurements (in the form of the H absolute magnitude) to determine albedos. Using these data we investigate the albedo and diameter distributions of the Main Belt. As observed previously, we find a change in the average albedo when comparing the inner, middle, and outer portions of the Main Belt. We also confirm that the albedo distribution of each region is strongly bimodal. We observe groupings of objects with similar albedos in regions of the Main Belt associated with dynamical breakup families. Asteroid families typically show a characteristic albedo for all members, but there are notable exceptions to this.