- ID:
- ivo://CDS.VizieR/J/ApJ/559/307
- Title:
- Sub-mm mapping in Orion B molecular cloud
- Short Name:
- J/ApJ/559/307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a survey of a 900 arcmin^2^ region of the Orion B molecular cloud, including NGC 2068, NGC 2071, and HH 24/25/26, at 850{mu}m using the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope. Following the techniques developed by Johnstone et al. (2000ApJ...545..327J), we identify 75 independent objects and compute size, flux, and degree of central concentration. Comparison with isothermal, pressure-confined, self-gravitating Bonnor-Ebert spheres implies that the clumps have internal temperatures of 20-40K and surface pressures 5.5<log(P/k)[CGS]<6.5. The clump masses span 0.2-12.3M_{sun}_ assuming typical dust temperatures and a dust emissivity {kappa}_850_=0.01cm^2^/g.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/559/A82
- Title:
- Sub-mm observations of IRS43 and IRS63
- Short Name:
- J/A+A/559/A82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A fundamental part of the study of star formation is to place young stellar objects in an evolutionary sequence. Establishing a robust evolutionary classification scheme allows us not only to understand how the Sun was born but also to predict what kind of main sequence star a given protostar will become. Traditionally, low-mass young stellar objects are classified according to the shape of their spectral energy distributions. Such methods are, however, prone to misclassification due to degeneracy and do not constrain the temporal evolution. More recently, young stellar objects have been classified based on envelope, disk, and stellar masses determined from resolved images of their continuum and line emission at submillimeter wavelengths. Through detailed modeling of two Class I sources, we aim at determining accurate velocity profiles and explore the role of freeze-out chemistry in such objects. We present new Submillimeter Array observations of the continuum and HCO^+^ line emission at 1.1mm toward two protostars, IRS 63 and IRS 43 in the Ophiuchus star forming region. The sources were modeled in detail using dust radiation transfer to fit the SED and continuum images and line radiation transfer to produce synthetic position-velocity diagrams. We used a chi^2^ search algorithm to find the best model fit to the data and to estimate the errors in the model variables. Our best fit models present disk, envelope, and stellar masses, as well as the HCO^+^ abundance and inclination of both sources. We also identify a ring structure with a radius of about 200AU in IRS 63. Conclusions. We find that freeze-out chemistry is important in IRS 63 but not for IRS 43. We show that the velocity field in IRS 43 is consistent with Keplerian rotation. Owing molecular depletion, it is not possible to draw a similar conclusion for IRS 63. We identify a ring-shaped structure in IRS 63 on the same spatial scale as the disk outer radius. No such structure is seen in IRS 43. We find that freeze-out chemistry is important in IRS 63 but not for IRS 43. We show that the velocity field in IRS 43 is consistent with Keplerian rotation. Owing molecular depletion, it is not possible to draw a similar conclusion for IRS 63. We identify a ring-shaped structure in IRS 63 on the same spatial scale as the disk outer radius. No such structure is seen in IRS 43.
- ID:
- ivo://CDS.VizieR/J/A+A/579/A115
- Title:
- SUDARE-VOICE variability-selection of AGN
- Short Name:
- J/A+A/579/A115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the most peculiar characteristics of active galactic nuclei (AGNs) is their variability over all wavelengths. This property has been used in the past to select AGN samples and is foreseen to be one of the detection techniques applied in future multi-epoch surveys, complementing photometric and spectroscopic methods. In this paper, we aim to construct and characterise an AGN sample using a multi-epoch dataset in the r band from the SUDARE-VOICE survey. Our work makes use of the VST monitoring programme of an area surrounding the Chandra Deep Field South to select variable sources. We use data spanning a six-month period over an area of 2 square degrees, to identify AGN based on their photometric variability. The selected sample includes 175 AGN candidates with magnitude r<23mag. We distinguish different classes of variable sources through their lightcurves, as well as X-ray, spectroscopic, SED, optical, and IR information overlapping with our survey. We find that 12% of the sample (21/175) is represented by supernovae (SN). Of the remaining sources, 4% (6/154) are stars, while 66% (102/154) are likely AGNs based on the available diagnostics. We estimate an upper limit to the contamination of the variability selected AGN sample =~34%, but we point out that restricting the analysis to the sources with available multi-wavelength ancillary information, the purity of our sample is close to 80% (102 AGN out of 128 non-SN sources with multi-wavelength diagnostics). Our work thus confirms the efficiency of the variability selection method, in agreement with our previous work on the COSMOS field. In addition we show that the variability approach is roughly consistent with the infrared selection.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/23
- Title:
- SUPER GOODS. IV. 850um data of CDFS X-ray sources
- Short Name:
- J/ApJ/887/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Chandra Deep Field (CDF)-S is the deepest X-ray image available and will remain so for the near future. We provide a spectroscopic (64.5%; 64% with spectral classifications) and photometric redshift catalog for the full 7Ms sample, but much of our analysis focuses on the central (off-axis angles <5.7') region, which contains a large, faint ALMA sample of 75 >4.5{sigma} 850{mu}m sources. We measure the 850{mu}m fluxes at the X-ray positions using the ALMA images, where available, or an ultradeep SCUBA-2 map. We find that the full X-ray sample produces ~10% of the 850{mu}m extragalactic background light. We separate the submillimeter-detected X-ray sources into star-forming galaxies and active galactic nuclei (AGNs) using a star formation rate (SFR) versus X-ray luminosity calibration for high-SFR galaxies. We confirm this separation using the X-ray photon indices. We measure the X-ray fluxes at the accurate positions of the 75 ALMA sources and detect 70% at >3{sigma} in either the 0.5-2 or 2-7keV bands. However, many of these may produce both their X-ray and submillimeter emission by star formation. Indeed, we find that only 20% of the ALMA sources have intermediate X-ray luminosities (rest-frame 8-28 keV luminosities of 10^42.5^-10^44^erg/s), and none has a high X-ray luminosity (>10^44^erg/s). Conversely, after combining the CDF-S with the CDF-N, we find extreme star formation (SFR>300M_{sun}_/yr) in some intermediate X-ray luminosity sources but not in any high X-ray luminosity sources. We argue that the quenching of star formation in the most luminous AGNs may be a consequence of the clearing of gas in these sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/749/121
- Title:
- Surface brightness profiles of z=2 galaxies
- Short Name:
- J/ApJ/749/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use deep Hubble Space Telescope Wide Field Camera 3 near-infrared imaging obtained of the GOODS-South field as part of the CANDELS survey to investigate a stellar mass-limited sample of quiescent galaxies at 1.5<z<2.5. We measure surface brightness profiles for these galaxies using a method that properly measures low surface brightness flux at large radii. We find that quiescent galaxies at z~2 very closely follow Sersic profiles, with n_median_=3.7, and have no excess flux at large radii. Their effective radii are a factor of ~4 smaller than those of low-redshift quiescent galaxies of similar mass. However, there is a significant spread in sizes ({sigma}_log_10_r_e__=0.24), with the largest z~2 galaxies lying close to the z=0 mass-size relation. We compare the stellar mass surface density profiles with those of massive elliptical galaxies in the Virgo Cluster and confirm that most of the mass growth which occurs between z~2 and z=0 must be due to accretion of material onto the outer regions of the galaxies. Additionally, we investigate the evolution in the size distribution of massive quiescent galaxies. We find that the minimum size growth required for z~2 quiescent galaxies to fall within the z=0 size distribution is a factor of ~2 smaller than the total median size growth between z~2 and z=0.
- ID:
- ivo://CDS.VizieR/J/ApJS/98/369
- Title:
- Survey of Markarian galaxies
- Short Name:
- J/ApJS/98/369
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results are presented from a multifrequency radio continuum survey of Markarian galaxies (MRKs) and are supplemented by IRAS infrared data from the Faint Source Survey. Radio data are presented for 899 MRKs observed at {nu}=4.755GHz with the NRAO-Green Bank 300 foot (91m) telescope, including nearly 88% of those objects in Markarian list VI-XIV. In addition, 1.415GHz measurements of 258 MRKs, over 30% of the MRKs accessible from NAIC-Arecibo, are reported. Radio continuum observations of smaller numbers of MRKs were made at 10.63GHz and at 23.1GHz and are also presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/687/230
- Title:
- Survey of M31 with Spitzer
- Short Name:
- J/ApJ/687/230
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the stellar population of M31 in a Spitzer Space Telescope survey utilizing IRAC and MIPS observations. Red supergiants are the brightest objects seen in the infrared; they are a prominent evolutionary phase. Due to their circumstellar envelopes, many of these radiate the bulk of their luminosity at IRAC wavelengths and do not stand out in the near-infrared or optically. Going fainter, we see large numbers of luminous asymptotic giant branch stars (AGB), many of which are known long-period variables. Relative to M33 the AGB carbon star population of M31 appears sparse, but this needs to be spectroscopically confirmed.
- ID:
- ivo://CDS.VizieR/J/ApJ/765/L26
- Title:
- Swift/BAT ultra-hard X-ray data from GOALS LIRGs
- Short Name:
- J/ApJ/765/L26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first analysis of the all-sky Swift Burst Alert Telescope (BAT) ultra-hard X-ray (14-195keV) data for a targeted list of objects. We find that the BAT data can be studied at three-times-fainter limits than in previous blind detection catalogs based on prior knowledge of source positions and using smaller energy ranges for source detection. We determine the active galactic nucleus (AGN) fraction in 134 nearby (z<0.05) luminous infrared galaxies (LIRGs) from the GOALS sample. We find that LIRGs have a higher detection frequency than galaxies matched in stellar mass and redshift at 14-195keV and 24-35keV. In agreement with work at other wavelengths, the AGN detection fraction increases strongly at high IR luminosity with half of the high-luminosity LIRGs (50%, 6/12, logL_IR_/L_{sun}_>11.8) detected. The BAT AGN classification shows 97% (37/38) agreement with Chandra and XMM-Newton AGN classification using hardness ratios or detection of an iron K{alpha} line. This confirms our statistical analysis and supports the use of the Swift/BAT all-sky survey to study fainter populations of any category of sources in the ultra-hard X-ray band. BAT AGNs in LIRGs tend to show higher column densities with 40%+/-9% showing 14-195 keV/2-10 keV hardness flux ratios suggestive of high or Compton-thick column densities (logN_H_>24/cm2), compared to only 12%+/-5% of non-LIRG BAT AGNs. We also find that using specific energy ranges of the BAT detector can yield additional sources over total band detections with 24% (5/21) of detections in LIRGs at 24-35keV not detected at 14-195keV.
- ID:
- ivo://CDS.VizieR/II/255
- Title:
- SWIRE ELAIS N1 Source Catalogs
- Short Name:
- II/255
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Spitzer Wide-area InfraRed Extragalactic survey (SWIRE; Lonsdale et al., 2003PASP..115..897L) Version 1.0 data products release includes an image atlas and a source catalogs from the first of the 6 SWIRE fields to be observed by Spitzer, the ELAIS-N1 field. The release includes both Spitzer IRAC and MIPS mid/far-infrared data products and also Ug'r'i'Z optical data covering the same regions of the sky from the Isaac Newton Telescope (INT) Wide-Field Survey (WFS; McMahon et al., 2001NewAR..45...97M; Gonzalez-Solares et al., 2004, MNRAS, in press). The Version 1.0 SWIRE ELAIS-N1 Source Catalogs have three parts: (1) a catalog including IRAC and MIPS 24{mu}m sources which have been band-merged together. The Spitzer source list has been positionally matched to the optical source list and we report optical position and 5-band magnitude data for each successful match. This catalog contains only sources lying with the region which has full coverage in all four IRAC bands; (2) a 70{mu}m catalog; and (3) a 160{mu}m catalog. The longer wavelength catalogs have not been band-merged with the IRAC+24{mu}m catalog or the optical source list at this time because of complex source confusion issues. The two MIPS-Ge catalogs cover the full area scanned by each MIPS-array, except for areas of low coverage around each edge, and are not restricted to the full IRAC coverage area. All data are available at http://data.spitzer.caltech.edu/popular/swire/20041027_enhanced_v1_EN1
- ID:
- ivo://CDS.VizieR/J/A+A/476/151
- Title:
- SWIRE ELAIS-S1 IR-peak galaxy IR fluxes
- Short Name:
- J/A+A/476/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Main data on the IR-peakers sample in the SWIRE ELAIS-S1 field. For each IR-peak galaxy, we report R band magnitude (AB units, from the ESIS survey, Berta et al., 2006A&A...451..881B), Spitzer SWIRE fluxes (Lonsdale et al., 2003PASP..115..897L, 2004ApJS..154...54L), photometric redshift (based on Hyper-z fit, Bolzonella et al., 2000A&A...363..476B), the stellar mass and its minimal-maximal range. The stellar mass estimate is based on mixed stellar population (MSP) synthesis (Berta et al., 2004A&A...418..913B). The minimal and maximal stellar masses are obtained by exploring the SFH-extinction parameter space with the Adaptive Simulated Annealing algorithm (Ingber et al., 2001, http://www.ingber.com/asa01_lecture.pdf). See the paper associated to these data for more details.
