- 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.
Number of results to display per page
Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/AJ/151/90
- Title:
- Spitzer and VRIJHK photometry of V582 Mon
- Short Name:
- J/AJ/151/90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the light and color evolution of the T Tauri binary KH 15D through photometry obtained at wavelengths between 0.55 and 8.0{mu}m. The data were collected with A Novel Dual Imaging CAMera (ANDICAM) on the 1.3m SMARTS telescope at Cerro-Tololo Inter-American Observatory and with InfraRed Array Camera on the Spitzer Space Telescope. We show that the system's circumbinary ring, which acts as a screen that covers and uncovers different portions of the binary orbit as the ring precesses, has reached an orientation where the brighter component (star B) fully or nearly fully emerges during each orbital cycle. The fainter component (star A) remains fully occulted by the screen at all phases. The leading and trailing edges of the screen move across the sky at the same rate of ~15m/s, consistent with expectation for a ring with a radius and width of ~4 au and a precession period of ~6500 years. Light and color variations continue to indicate that the screen is sharp edged and opaque at VRIJH wavelengths. However, we find an increasing transparency of the ring edge at 2.2, 3.6, and 4.5{mu}m. Reddening seen at the beginning of the eclipse that occurred during the CSI 2264 campaign particularly suggests selective extinction by a population of large dust grains. Meanwhile, the gradual bluing observed while star B is setting is indicative of forward scattering effects at the edge of the ring. The spectral energy distribution of the system at its bright phase shows no evidence of infrared excess emission that can be attributed to radiation from the ring or other dust component out to 8{mu}m.
- ID:
- ivo://CDS.VizieR/J/AJ/152/142
- Title:
- Spitzer and WISE light curves of Neptune
- Short Name:
- J/AJ/152/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Spitzer Space Telescope in 2016 February to obtain high cadence, high signal-to-noise, 17hr duration light curves of Neptune at 3.6 and 4.5{mu}m. The light curve duration was chosen to correspond to the rotation period of Neptune. Both light curves are slowly varying with time, with full amplitudes of 1.1mag at 3.6{mu}m and 0.6mag at 4.5{mu}m. We have also extracted sparsely sampled 18hr light curves of Neptune at W1 (3.4{mu}m) and W2 (4.6{mu}m) from the Wide-feld Infrared Survey Explorer (WISE)/NEOWISE archive at six epochs in 2010-2015. These light curves all show similar shapes and amplitudes compared to the Spitzer light curves but with considerable variation from epoch to epoch. These amplitudes are much larger than those observed with Kepler/K2 in the visible (amplitude ~0.02mag) or at 845nm with the Hubble Space Telescope (HST) in 2015 and at 763nm in 2016 (amplitude ~0.2mag). We interpret the Spitzer and WISE light curves as arising entirely from reflected solar photons, from higher levels in Neptune's atmosphere than for K2. Methane gas is the dominant opacity source in Neptune's atmosphere, and methane absorption bands are present in the HST 763 and 845nm, WISE W1, and Spitzer 3.6{mu}m filters.
- ID:
- ivo://CDS.VizieR/J/ApJS/218/33
- Title:
- Spitzer-CANDELS catalog within 5 deep fields
- Short Name:
- J/ApJS/218/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Spitzer-Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (S-CANDELS; PI G.Fazio) is a Cycle 8 Exploration Program designed to detect galaxies at very high redshifts (z>5). To mitigate the effects of cosmic variance and also to take advantage of deep coextensive coverage in multiple bands by the Hubble Space Telescope (HST) Multi-cycle Treasury Program CANDELS, S-CANDELS was carried out within five widely separated extragalactic fields: the UKIDSS Ultra-deep Survey, the Extended Chandra Deep Field South, COSMOS, the HST Deep Field North, and the Extended Groth Strip. S-CANDELS builds upon the existing coverage of these fields from the Spitzer Extended Deep Survey (SEDS), a Cycle 6 Exploration Program, by increasing the integration time from SEDS' 12hr to a total of 50hr but within a smaller area, 0.16deg^2^. The additional depth significantly increases the survey completeness at faint magnitudes. This paper describes the S-CANDELS survey design, processing, and publicly available data products. We present Infrared Array Camera (IRAC) dual-band 3.6+4.5{mu}m catalogs reaching to a depth of 26.5 AB mag. Deep IRAC counts for the roughly 135000 galaxies detected by S-CANDELS are consistent with models based on known galaxy populations. The increase in depth beyond earlier Spitzer/IRAC surveys does not reveal a significant additional contribution from discrete sources to the diffuse Cosmic Infrared Background (CIB). Thus it remains true that only roughly half of the estimated CIB flux from COBE/DIRBE is resolved.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/30
- Title:
- Spitzer catalog of Herschel star-forming galaxies
- Short Name:
- J/ApJS/244/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The largest Herschel extragalactic surveys, H-ATLAS and HerMES, have selected a sample of "ultrared" dusty star-forming galaxies (DSFGs) with rising SPIRE flux densities (S_500_>S_350_>S_250_; the so-called "500{mu}m risers") as an efficient way for identifying DSFGs at higher redshift (z>4). In this paper, we present a large Spitzer follow-up program of 300 Herschel ultrared DSFGs. We have obtained high-resolution Atacama Large Millimeter/submillimeter Array, Northern Extended Millimeter Array, and SMA data for 63 of them, which allow us to securely identify the Spitzer/IRAC counterparts and classify them as gravitationally lensed or unlensed. Within the 63 ultrared sources with high-resolution data, ~65% appear to be unlensed and ~27% are resolved into multiple components. We focus on analyzing the unlensed sample by directly performing multiwavelength spectral energy distribution modeling to derive their physical properties and compare with the more numerous z~2 DSFG population. The ultrared sample has a median redshift of 3.3, stellar mass of 3.7x10^11^M_{sun}_, star formation rate (SFR) of 730M_{sun}_/yr, total dust luminosity of 9.0x10^12^L_{sun}_, dust mass of 2.8x10^9^M_{sun}_, and V-band extinction of 4.0, which are all higher than those of the ALESS DSFGs. Based on the space density, SFR density, and stellar mass density estimates, we conclude that our ultrared sample cannot account for the majority of the star-forming progenitors of the massive, quiescent galaxies found in infrared surveys. Our sample contains the rarer, intrinsically most dusty, luminous, and massive galaxies in the early universe that will help us understand the physical drivers of extreme star formation.
- ID:
- ivo://CDS.VizieR/J/ApJS/177/551
- Title:
- Spitzer c2d survey of Lupus dark clouds
- Short Name:
- J/ApJS/177/551
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present c2d Spitzer IRAC observations of the Lupus I, III, and IV dark clouds and discuss them in combination with optical, near-infrared, and c2d MIPS data. With the Spitzer data, the new sample contains 159 stars, 4 times larger than the previous one. It is dominated by low- and very low mass stars, and it is complete down to M~0.1M_{sun}_. We find 30%-40% binaries with separations between 100 and 2000AU with no apparent effect on the disk properties of the members. A large majority of the objects are Class II or III objects, with only 20(12%) Class I or flat-spectrum sources. The disk sample is complete down to "debris"-like systems in stars as small as M~0.2M_{sun}_ and includes substellar objects with larger IR excesses. The disk fraction in Lupus is 70%-80%, consistent with an age of 1-2Myr. However, the young population contains 20% optically thick accretion disks and 40% relatively less flared disks. A growing variety of inner disk structures is found for larger inner disk clearings for equal disk masses.
- ID:
- ivo://CDS.VizieR/J/ApJ/669/493
- Title:
- Spitzer/Chandra YSOs in Serpens cloud core
- Short Name:
- J/ApJ/669/493
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer and Chandra observations of the nearby (~260pc) embedded stellar cluster in the Serpens cloud core. We observed, using Spitzer's IRAC and MIPS instruments, in six wavelength bands from 3 to 70um, to detect thermal emission from circumstellar disks and protostellar envelopes and to classify stars using color-color diagrams and SEDs. These data are combined with Chandra observations to examine the effects of circumstellar disks on stellar X-ray properties. Young diskless stars were also identified from their increased X-ray emission. We have identified 138 YSOs in Serpens: 22 Class 0/I, 16 flat-spectrum, 62 Class II, 17 transition disk, and 21 Class III stars; 60 of these exhibit X-ray emission.
