- ID:
- ivo://CDS.VizieR/J/ApJ/691/1387
- Title:
- Spectroscopy of the Galactic bar. I.
- Short Name:
- J/ApJ/691/1387
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Fabry-Perot absorption line imaging spectroscopy to measure radial velocities using the CaII line in 3360 stars toward three lines of sight in the Milky Way's bar: Baade's Window and offset position at (l,b)~(+/-5.0,-3.5{deg}). This sample includes 2488 bar red clump giants, 339 bar M/K-giants, and 318 disk main-sequence stars. We measure the first four moments of the stellar velocity distribution of the red clump giants, and find it to be symmetric and flat-topped. We also measure the line-of-sight average velocity and dispersion of the red clump giants as a function of distance in the bar.
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- ID:
- ivo://CDS.VizieR/J/ApJ/668/853
- Title:
- Spectroscopy of UltraStrong Emission Line galaxies
- Short Name:
- J/ApJ/668/853
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the results of a narrowband search for ultrastrong emission line galaxies (USELs) with EW(H{beta})>=30{AA}. A total of 542 candidate galaxies are found in a one-half square degree survey using two ~120{AA} filters centered at 8150 and 9140{AA} with Subaru SuprimeCam. Follow-up spectroscopy for randomly selected objects in the candidate sample with Keck II DEIMOS shows that they consist of [OIII] {lambda}5007-, [OII] {lambda}3727-, and H{alpha}-selected strong emission line galaxies at intermediate redshift (z<1) and Ly{alpha}-emitting galaxies at high redshift (z>>5).
- ID:
- ivo://CDS.VizieR/J/ApJ/710/1142
- Title:
- SpeX spectroscopy of low mass binaries. I.
- Short Name:
- J/ApJ/710/1142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the identification of 17 candidate brown dwarf binaries whose components straddle the L dwarf/T dwarf transition. These sources were culled from a large near-infrared spectral sample of L and T dwarfs observed with the Infrared Telescope Facility SpeX spectrograph. Candidates were selected on the basis of spectral ratios which segregate known (resolved) L dwarf/T dwarf pairs from presumably single sources. Composite templates, constructed by combining 13581 pairs of absolute flux-calibrated spectra, are shown to provide statistically superior fits to the spectra of our 17 candidates as compared to single templates. Ten of these candidates appear to have secondary components that are significantly brighter than their primaries over the 1.0-1.3um band, indicative of rapid condensate depletion at the L dwarf/T dwarf transition. Our results support prior indications of enhanced multiplicity amongst early-type T dwarfs; 53+/-7% of the T0-T4 dwarfs in our spectral sample are found to be either resolved or unresolved (candidate) pairs, although this is consistent with an intrinsic (volume complete) brown dwarf binary fraction of only 15%. If verified, this sample of spectral binaries more than doubles the number of known L dwarf/T dwarf transition pairs, enabling a broader exploration of this poorly understood phase of brown dwarf atmospheric evolution.
- ID:
- ivo://CDS.VizieR/J/ApJS/225/1
- Title:
- SpIES: the Spitzer IRAC Equatorial Survey
- Short Name:
- J/ApJS/225/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the first data release from the Spitzer-IRAC Equatorial Survey (SpIES); a large-area survey of ~115deg^2^ in the Equatorial SDSS Stripe 82 field using Spitzer during its "warm" mission phase. SpIES was designed to probe sufficient volume to perform measurements of quasar clustering and the luminosity function at z>=3 to test various models for "feedback" from active galactic nuclei (AGNs). Additionally, the wide range of available multi-wavelength, multi-epoch ancillary data enables SpIES to identify both high-redshift (z>=5) quasars as well as obscured quasars missed by optical surveys. SpIES achieves 5{sigma} depths of 6.13uJy (21.93 AB magnitude) and 5.75uJy (22.0 AB magnitude) at 3.6 and 4.5um, respectively --depths significantly fainter than the Wide-field Infrared Survey Explorer (WISE). We show that the SpIES survey recovers a much larger fraction of spectroscopically confirmed quasars (~98%) in Stripe 82 than are recovered by WISE (~55%). This depth is especially powerful at high-redshift (z>=3.5), where SpIES recovers 94% of confirmed quasars, whereas WISE only recovers 25%. Here we define the SpIES survey parameters and describe the image processing, source extraction, and catalog production methods used to analyze the SpIES data. In addition to this survey paper, we release 234 images created by the SpIES team and three detection catalogs: a 3.6um only detection catalog containing ~6.1 million sources, a 4.5um only detection catalog containing ~6.5 million sources, and a dual-band detection catalog containing ~5.4 million sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/685/958
- Title:
- Spitzer and Chandra sources in galactic center
- Short Name:
- J/ApJ/685/958
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have studied the correlation between 2357 Chandra X-ray point sources in a 40x40pc field and ~20000 infrared sources we observed in the corresponding subset of our 2x1.4{deg} Spitzer/IRAC Galactic Center Survey at 3.6-8.0um, using various spatial and X-ray hardness thresholds. The correlation was determined for source separations of less than 0.5", 1", or 2". Only the soft X-ray sources show any correlation with infrared point sources on these scales, and that correlation is very weak. The upper limit on hard X-ray sources that have infrared counterparts is <1.7% (3{sigma}). However, because of the confusion limit of the IR catalog, we only detect IR sources with absolute magnitudes <~1. As a result, a stronger correlation with fainter sources cannot be ruled out. Only one compact IR source, IRS 13, coincides with any of the dozen prominent X-ray emission features in the 3x3pc region centered on Sgr A*, and the diffuse X-ray and IR emission around Sgr A* seems to be anticorrelated on a few-arcsecond scale. We compare our results with previous identifications of near-infrared companions to Chandra X-ray sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/768/25
- Title:
- Spitzer and Herschel observations of debris disks
- Short Name:
- J/ApJ/768/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the collisional decay of disk mass and infrared emission in debris disks. With models, we show that the rate of the decay varies throughout the evolution of the disks, increasing its rate up to a certain point, which is followed by a leveling off to a slower value. The total disk mass falls off {prop.to}t^-0.35^ at its fastest point (where t is time) for our reference model, while the dust mass and its proxy -the infrared excess emission- fades significantly faster ({prop.to}t^-0.8^). These later level off to a decay rate of M_tot_(t){prop.to}t^-0.08^ and M_dust_(t) or L_ir_(t){prop.to}t^-0.6^. This is slower than the {prop.to}t.^-1^ decay given for all three system parameters by traditional analytic models. We also compile an extensive catalog of Spitzer and Herschel 24, 70, and 100{mu}m observations. Assuming a log-normal distribution of initial disk masses, we generate model population decay curves for the fraction of stars harboring debris disks detected at 24{mu}m. We also model the distribution of measured excesses at the far-IR wavelengths (70-100{mu}m) at certain age regimes. We show general agreement at 24{mu}m between the decay of our numerical collisional population synthesis model and observations up to a Gyr. We associate offsets above a Gyr to stochastic events in a few select systems. We cannot fit the decay in the far-infrared convincingly with grain strength properties appropriate for silicates, but those of water ice give fits more consistent with the observations (other relatively weak grain materials would presumably also be successful). The oldest disks have a higher incidence of large excesses than predicted by the model; again, a plausible explanation is very late phases of high dynamical activity around a small number of stars. Finally, we constrain the variables of our numerical model by comparing the evolutionary trends generated from the exploration of the full parameter space to observations. Amongst other results, we show that erosive collisions are dominant in setting the timescale of the evolution and that planetesimals on the order of 100 km in diameter are necessary in the cascades for our population synthesis models to reproduce the observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/685/1005
- Title:
- Spitzer and high-mass star forming regions
- Short Name:
- J/ApJ/685/1005
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer Space Telescope IRAC and MIPS observations toward a sample of nine high-mass star forming regions at a distance of around 2kpc. Based on IRAC and MIPS 24um photometric results and 2MASS JHKs data, we carry out a census of young stellar objects (YSOs) in a 5'x5' field toward each region. Toward seven out of the nine regions, we detect parsec-sized clusters with around 20 YSOs surrounded by a more extended and sparse distribution of young stars and protostars. For the other two regions, IRAS 20126+4104 and IRAS 22172+5549, the former has the lowest number of YSOs in the sample and shows no obvious cluster, and the latter appears to be part of a larger, potentially more evolved cluster.
- ID:
- ivo://CDS.VizieR/J/ApJ/778/96
- Title:
- Spitzer and NEWFIRM observations of NGC 6334
- Short Name:
- J/ApJ/778/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents a study of the rate and efficiency of star formation in the NGC 6334 star-forming region. We obtained observations at J, H, and K_s_ taken with the NOAO Extremely Wide-Field Infrared Imager and combined them with observations taken with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope at wavelengths = 3.6, 4.5, 5.8, and 8.0{mu}m. We also analyzed previous observations taken at 24{mu}m using the Spitzer MIPS camera as part of the MIPSGAL survey. We have produced a point source catalog with >700000 entries. We have identified 2283 young stellar object (YSO) candidates, 375 Class I YSOs, and 1908 Class II YSOs using a combination of existing IRAC-based color classification schemes that we have extended and validated to the near-IR for use with warm Spitzer data. We have identified multiple new sites of ongoing star formation activity along filamentary structures extending tens of parsecs beyond the central molecular ridge of NGC 6334. By mapping the extinction, we derived an estimate for the gas mass, 2.2x10^5^M_{sun}_. The heavy concentration of protostars along the dense filamentary structures indicates that NGC 6334 may be undergoing a "mini-starburst" event with {Sigma}_SFR_>8.2M_{sun}_M/yr/pc2 and SFE>0.10. We have used these estimates to place NGC 6334 in the Kennicutt-Schmidt diagram to help bridge the gap between observations of local low-mass star-forming regions and star formation in other galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/805/77
- Title:
- Spitzer 3.6 and 4.5um monitoring of 5 stars
- Short Name:
- J/ApJ/805/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Luminous debris disks of warm dust in the terrestrial planet zones around solar-like stars were recently found to vary, which is indicative of ongoing large-scale collisions of rocky objects. We use Spitzer 3.6 and 4.5um time-series observations in 2012 and 2013 (extended to 2014 in one case) to monitor five more debris disks with unusually high fractional luminosities ("extreme debris disk"), including P1121 in the open cluster M47 (80 Myr), HD15407A in the AB Dor moving group (80Myr), HD 23514 in the Pleiades (120Myr), HD145263 in the Upper Sco Association (10Myr), and the field star BD+20 307 (>~1Gyr). Together with the published results for ID8 in NGC2547 (35Myr), this makes the first systematic time-domain investigation of planetary impacts outside the solar system. Significant variations with timescales shorter than a year are detected in five out of the six extreme debris disks we monitored. However, different systems show diverse sets of characteristics in the time domain, including long-term decay or growth, disk temperature variations, and possible periodicity.
- ID:
- ivo://CDS.VizieR/J/AJ/131/250
- Title:
- Spitzer 70 and 160um observations in xFLS
- Short Name:
- J/AJ/131/250
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 70 and 160{mu}m observations from the Spitzer extragalactic First Look Survey (xFLS). The data reduction techniques and the methods for producing co-added mosaics and source catalogs are discussed. Currently, 26% of the 70{mu}m sample and 49% of the 160{mu}m-selected sources have redshifts. The majority of sources with redshifts are star-forming galaxies at z<0.5, while about 5% have infrared colors consistent with active galactic nuclei. The observed infrared colors agree with the spectral energy distributions (SEDs) of local galaxies previously determined from IRAS and Infrared Space Observatory data.
