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531. Broad Absorption Line Quasars from SDSS
ID:
ivo://CDS.VizieR/J/AJ/125/1711
Title:
Broad Absorption Line Quasars from SDSS
Short Name:
J/AJ/125/1711
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 224 broad absorption line quasars (BALQSOs) from the Sloan Digital Sky Survey's Early Data Release Quasar Catalog, (Schneider et al., 2002, Cat. <J/AJ/123/567>) including a relatively complete and homogeneous subsample of 131 BALQSOs. Since the identification of BALQSOs is subject to considerable systematic uncertainties, we attempt to create a complete sample of SDSS BALQSOs by combining the results of two automated selection algorithms and a by-eye classification scheme. One of these automated algorithms finds broad absorption line troughs by comparing with a composite quasar spectrum. We present the details of this algorithm and compare this method with one that uses a power-law fit to the continuum. The BALQSOs in our sample are further classified as high-ionization BALQSOs (HiBALs), low-ionization BALQSOs (LoBALs), and BALQSOs with excited iron absorption features (FeLoBALs); composite spectra of each type are presented. We further present a study of the properties of the BALQSOs in terms of the balnicity distribution, which rises with decreasing balnicity. This distribution of balnicities suggests that the fraction of quasars with intrinsic outflows may be significantly underestimated. The balnicity index defined by Weymann et al. (1991ApJ...373...23W) amounts to a sort of equivalent width: a quasar is declared to be a BAL when its balnicity index is >=0.
532. Broadband photometry of Neptune from K2
ID:
ivo://CDS.VizieR/J/AJ/153/149
Title:
Broadband photometry of Neptune from K2
Short Name:
J/AJ/153/149
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report here on our search for excess power in photometry of Neptune collected by the K2 mission that may be due to intrinsic global oscillations of the planet Neptune. To conduct this search, we developed new methods to correct for instrumental effects such as intrapixel variability and gain variations. We then extracted and analyzed the time-series photometry of Neptune from 49 days of nearly continuous broadband photometry of the planet. We find no evidence of global oscillations and place an upper limit of ~5ppm at 1000{mu}Hz for the detection of a coherent signal. With an observed cadence of 1 minute and a point-to-point scatter of less than 0.01%, the photometric signal is dominated by reflected light from the Sun, which is in turn modulated by atmospheric variability of Neptune at the 2% level. A change in flux is also observed due to the increasing distance between Neptune and the K2 spacecraft and the solar variability with convection-driven solar p modes present.
533. Broad-line AGN with host galaxy colors
ID:
ivo://CDS.VizieR/J/ApJ/763/133
Title:
Broad-line AGN with host galaxy colors
Short Name:
J/ApJ/763/133
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first quantified, statistical map of broad-line active galactic nucleus (AGN) frequency with host galaxy color and stellar mass in nearby (0.01<z<0.11) galaxies. Aperture photometry and z-band concentration measurements from the Sloan Digital Sky Survey are used to disentangle AGN and galaxy emission, resulting in estimates of uncontaminated galaxy rest-frame color, luminosity, and stellar mass. Broad-line AGNs are distributed throughout the blue cloud and green valley at a given stellar mass, and are much rarer in quiescent (red sequence) galaxies. This is in contrast to the published host galaxy properties of weaker narrow-line AGNs, indicating that broad-line AGNs occur during a different phase in galaxy evolution. More luminous broad-line AGNs have bluer host galaxies, even at fixed mass, suggesting that the same processes that fuel nuclear activity also efficiently form stars. The data favor processes that simultaneously fuel both star formation activity and rapid supermassive black hole accretion. If AGNs cause feedback on their host galaxies in the nearby universe, the evidence of galaxy-wide quenching must be delayed until after the broad-line AGN phase.
534. Brown dwarf atmosphere monitoring (BAM)
ID:
ivo://CDS.VizieR/J/A+A/566/A111
Title:
Brown dwarf atmosphere monitoring (BAM)
Short Name:
J/A+A/566/A111
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the SofI instrument on the 3.5m New Technology Telescope, we have conducted an extensive near-infrared monitoring survey of an unbiased sample of 69 brown dwarfs spanning the L0 to T8 spectral range, with at least one example of each spectral type. Each target was observed for a 2-4 hour period in the Js-band, and the median photometric precision of the data is ~0.7%. A total of 14 brown dwarfs were identified as variables with min-to-max amplitudes ranging from 1.7% to 10.8% over the observed duration. All variables satisfy a statistical significance threshold with a p-value <=5% based on comparison with a median reference star light curve. Approximately half of the variables show pure sinusoidal amplitude variations similar to 2MASSJ2139+0220, and the remainder show multi-component variability in their light curves similar to SIMPJ0136+0933.
535. Brown Dwarfs in ChaI Dark Cloud
ID:
ivo://CDS.VizieR/J/A+A/416/555
Title:
Brown Dwarfs in ChaI Dark Cloud
Short Name:
J/A+A/416/555
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a multiband survey for brown dwarfs in the Chamaeleon I dark cloud with the Wide Field Imager (WFI) camera at the ESO/MPG 2.2-m telescope on La Silla (Chile) on 28-May to 03-Jun 1999. The survey has revealed a substantial population of brown dwarfs in this southern star-forming region. Candidates were selected from R, I and H{alpha} imaging observations. We also observed in two medium-band filters, M855 and M915, for spectral type determination. The former filter covers a wavelength range containing spectral features characteristic of M-dwarfs, while the latter lies in a relatively featureless wavelength region for these late-type objects. A correlation was found between spectral type and (M855-M915) colour index for mid- to late M-type objects and early L-type dwarfs. With this method, we identify most of our object candidates as being of spectral type M5 or later. Our results show that there is no strong drop in the number of objects for the latest spectral types, hence brown dwarfs may be as abundant as low-mass stars in this region. Also, both kind of objects have a similar spatial distribution. We derive an index {alpha}=0.6+/-0.1 of the mass function in this region of dispersed star formation, in good agreement with the values obtained in other star forming regions and young clusters. Some of the brown dwarfs have strong H{alpha} emission, suggesting mass accretion. For objects with published infrared photometry, we find that strong H{alpha} emission is related to a mid-infrared excess, indicative of the existence of a circumstellar disk.
536. Brown dwarfs in the 2MASS Survey
ID:
ivo://CDS.VizieR/J/AJ/127/2856
Title:
Brown dwarfs in the 2MASS Survey
Short Name:
J/AJ/127/2856
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the discovery of seven new T dwarfs identified in the Two Micron All Sky Survey (Cat. <II/246>). Low-resolution (R~150) 0.8-2.5{mu}m spectroscopy obtained with the Infrared Telescope Facility (IRTF) SpeX instrument reveals the characteristic H_2_O and CH_4_ bands in the spectra of these brown dwarfs. Comparison with spectral standards observed with the same instrument enables us to derive classifications of T3 to T7 for the objects in this sample. Moderate-resolution (R~1200) near-infrared spectroscopy for a subset of these discoveries reveal K I line strengths consistent with previously observed trends with spectral type. Follow-up imaging observations provide proper-motion measurements for these sources, ranging from less than 0.1" to 1.55"/yr. One object, 2MASS 0034+0523, has a spectrophotometric distance placing it within 10pc of the Sun. This source also exhibits a depressed K-band peak reminiscent of the peculiar T dwarf 2MASS 0937+2931 and may be a metal-poor or old, high-mass brown dwarf. We also present low-resolution SpeX data for a set of M- and L-type dwarf, subdwarf, and giant comparison stars used to classify 59 additional candidates identified as background stars. These are primarily M5-M8.5 dwarfs, many exhibiting H I Pa^{gamma}^, but include three candidate ultracool M subdwarfs and one possible early-type L subdwarf.
537. Brown dwarfs with spectral type later than T6
ID:
ivo://CDS.VizieR/J/ApJ/842/118
Title:
Brown dwarfs with spectral type later than T6
Short Name:
J/ApJ/842/118
Date:
21 Oct 2021
Publisher:
CDS
Description:
The survey of the mid-infrared sky by the Wide-field Infrared Survey Explorer (WISE) led to the discovery of extremely cold, low-mass brown dwarfs, classified as Y dwarfs, which extend the T class to lower temperatures. Twenty-four Y dwarfs are known at the time of writing. Here we present improved parallaxes for four of these, determined using Spitzer images. We give new photometry for four late-type T and three Y dwarfs and new spectra of three Y dwarfs, obtained at Gemini Observatory. We also present previously unpublished photometry taken from HST, ESO, Spitzer, and WISE archives of 11 late-type T and 9 Y dwarfs. The near-infrared data are put onto the same photometric system, forming a homogeneous data set for the coolest brown dwarfs. We compare recent models to our photometric and spectroscopic data set. We confirm that nonequilibrium atmospheric chemistry is important for these objects. Nonequilibrium cloud-free models reproduce well the near-infrared spectra and mid-infrared photometry for the warmer Y dwarfs with 425<=T_eff_(K)<=450. A small amount of cloud cover may improve the model fits in the near-infrared for the Y dwarfs with 325<=T_eff_(K)<=375. Neither cloudy nor cloud-free models reproduce the near-infrared photometry for the T_eff_=250K Y dwarf WISEJ085510.83-071442.5 (W0855). We use the mid-infrared region, where most of the flux originates, to constrain our models of W0855. We find that W0855 likely has a mass of 1.5-8 Jupiter masses and an age of 0.3-6Gyr. The Y dwarfs with measured parallaxes are within 20pc of the Sun and have tangential velocities typical of the thin disk. The metallicities and ages we derive for the sample are generally solar-like. We estimate that the known Y dwarfs are 3 to 20 Jupiter-mass objects with ages of 0.6-8.5Gyr.
538. BR photometry and redshifts of IDS galaxies
ID:
ivo://CDS.VizieR/J/A+A/454/453
Title:
BR photometry and redshifts of IDS galaxies
Short Name:
J/A+A/454/453
Date:
21 Oct 2021
Publisher:
CDS
Description:
The IRAS Deep Survey (IDS) of the North Ecliptic Pole region remains one of the deepest complete far-infrared-selected galaxy samples available. ISOCAM observations in the LW3 filter (12-18{mu}m) of 3.2'x3.2' fields centered on the nominal positions of 94 out of the 98 IDS sources yielding 116 ISOCAM detections. The resulting sample has allowed us to assess the source reliability, identify confusion effects, and pinpoint optical counterparts. To fully exploit the potential of this sample for investigating galaxy evolution, we carried out optical observations of candidate identifications to 100 out of the 116 ISOCAM sources. Optical imaging was acquired for 88 galaxies in 54 IDS fields: 44 galaxies were imaged in both the B- and the R-band, 33 only in the R-band, and 11 only in the B-band. These observations aimed at extending the MIR/FIR spectral energy distribution to the optical region and achieving morphological information. In addition, spectra were obtained for 65 IDS fields, 20 of which had not been observed before. Redshifts were measured for the 85 galaxies found within the positional error circles of 77 ISOCAM sources detected in those IDS fields.
539. BR photometry in Coma, A2199 & AWM5 clusters
ID:
ivo://CDS.VizieR/J/AJ/117/75
Title:
BR photometry in Coma, A2199 & AWM5 clusters
Short Name:
J/AJ/117/75
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a study on galaxy interactions, tides, and other processes that produce luminous fine-scale substructures in the galaxy clusters: Coma, Perseus, Abell 2199, AWM 3, and AWM 5. All unusual structures in these clusters can be categorized into seven morphologies: interacting galaxies, multiple galaxies (noninteracting), distorted galaxies, tailed galaxies, line galaxies, dwarf galaxy groups, and galaxy aggregates. The various morphologies are described, and a catalog is presented, of 248 objects in these five clusters along with color, and positional information obtained from CCD images taken with the WIYN 3.5 m telescope in broadband B and R filters.
540. BR photometry of Abell 2104
ID:
ivo://CDS.VizieR/J/A+A/363/440
Title:
BR photometry of Abell 2104
Short Name:
J/A+A/363/440
Date:
21 Oct 2021
Publisher:
CDS
Description:
The cluster Abell 2104 is one of the lowest redshift clusters (z=0.153) known to have a gravitational lensing arc. We present detailed analysis of the cluster properties such as the gravitational potential using the X-ray data from ROSAT (HRI) and ASCA, as well as optical imaging and spectroscopic data from the CFHT.