- ID:
- ivo://CDS.VizieR/J/ApJS/228/7
- Title:
- Multi-wavelength data in CANDELS COSMOS field
- Short Name:
- J/ApJS/228/7
- Date:
- 03 Nov 2021 08:58:30
- Publisher:
- CDS
- Description:
- We present a multi-wavelength photometric catalog in the COSMOS field as part of the observations by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. The catalog is based on Hubble Space Telescope Wide Field Camera 3 (HST/WFC3) and Advanced Camera for Surveys observations of the COSMOS field (centered at RA:10:00:28, DEC:+02:12:21). The final catalog has 38671 sources with photometric data in 42 bands from UV to the infrared (~0.3-8{mu}m). This includes broadband photometry from HST, CFHT, Subaru, the Visible and Infrared Survey Telescope for Astronomy, and Spitzer Space Telescope in the visible, near-infrared, and infrared bands along with intermediate- and narrowband photometry from Subaru and medium-band data from Mayall NEWFIRM. Source detection was conducted in the WFC3 F160W band (at 1.6{mu}m) and photometry is generated using the Template FITting algorithm. We further present a catalog of the physical properties of sources as identified in the HST F160W band and measured from the multi-band photometry by fitting the observed spectral energy distributions of sources against templates.
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- ID:
- ivo://CDS.VizieR/J/AJ/144/101
- Title:
- Multiwavelength data of IRAS 20050+2720 young SFR
- Short Name:
- J/AJ/144/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IRAS 20050+2720 is young star-forming region at a distance of 700pc without apparent high-mass stars. We present results of our multi-wavelength study of IRAS 20050+2720 which includes observations by Chandra and Spitzer, and Two Micron All Sky Survey and UBVRI photometry. In total, about 300 young stellar objects (YSOs) in different evolutionary stages are found. We characterize the distribution of YSOs in this region using a minimum spanning tree analysis. We newly identify a second cluster core, which consists mostly of class II objects, about 10' from the center of the cloud. YSOs of earlier evolutionary stages are more clustered than more evolved objects. The X-ray luminosity function (XLF) of IRAS 20050+2720 is roughly lognormal, but steeper than the XLF of the more massive Orion Nebula complex. IRAS 20050+2720 shows a lower N_H_/A_K_ ratio compared with the diffuse interstellar medium.
- ID:
- ivo://CDS.VizieR/J/A+A/600/A93
- Title:
- Multiwavelength fluxes of RCW120
- Short Name:
- J/A+A/600/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The expansion of HII regions can trigger the formation of stars. An overdensity of young stellar objects (YSOs) is observed at the edges of HII regions but the mechanisms that give rise to this phenomenon are not clearly identified. Moreover, it is difficult to establish a causal link between HII-region expansion and the star formation observed at the edges of these regions. A clear age gradient observed in the spatial distribution of young sources in the surrounding might be a strong argument in favor of triggering. We have observed the Galactic HII region RCW120 with Herschel PACS and SPIRE photometers at 70, 100, 160, 250, 350 and 500um. We produced temperature and H_2_ column density maps and use the getsources algorithm to detect compact sources and measure their fluxes at Herschel wavelengths. We have complemented these fluxes with existing infrared data. Fitting their spectral energy distributions (SEDs) with a modified blackbody model, we derived their envelope dust temperature and envelope mass. We computed their bolometric luminosities and discuss their evolutionary stages. The Herschel data, with their unique sampling of the far infrared domain, have allowed us to characterize the properties of compact sources observed towards RCW120 for the first time. We have also been able to determine the envelope temperature, envelope mass and evolutionary stage of these sources. Using these properties we have shown that the density of the condensations that host star formation is a key parameter of the star-formation history, irrespective of their projected distance to the ionizing stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/586/794
- Title:
- Multiwavelength luminosities of galaxies
- Short Name:
- J/ApJ/586/794
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I have assembled a diverse sample of galaxies from the literature with far-ultraviolet (FUV), optical, infrared (IR), and radio luminosities to explore the calibration of radio-derived and IR-derived star formation (SF) rates and the origin of the radio-IR correlation. By comparing the 8-1000{mu}m IR, which samples dust-reprocessed starlight, with direct stellar FUV emission, I show that the IR traces most of the SF in luminous ~L* galaxies but traces only a small fraction of the SF in faint ~0.01L* galaxies. If radio emission were a perfect SF rate indicator, this effect would cause easily detectable curvature in the radio-IR correlation. Yet, the radio-IR correlation is nearly linear. This implies that the radio flux from low-luminosity galaxies is substantially suppressed, compared to brighter galaxies. This is naturally interpreted in terms of a decreasing efficiency of nonthermal radio emission in faint galaxies. Thus, the linearity of the radio-IR correlation is a conspiracy: both indicators underestimate the SF rate at low luminosities. SF rate calibrations that take into account this effect are presented, along with estimates of the random and systematic error associated with their use.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/623
- Title:
- Multiwavelength measurement of galaxy structure
- Short Name:
- J/MNRAS/435/623
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We demonstrate a new multiwavelength technique for two-dimensional parametric modelling of galaxy surface-brightness profiles, which we have incorporated into the widely used software GALFIT. Our new method, named GALFITM, extends GALFIT3's current single-band fitting process by simultaneously using multiple images of the same galaxy to constrain a wavelength-dependent model. Each standard profile parameter may vary as a function of wavelength, with a user-definable degree of smoothness, from constant to fully free. The performance of GALFITM is evaluated by fitting elliptical Sersic profiles to ugriz imaging data for 4026 galaxies, comprising the original Sloan Digital Sky Survey (SDSS) imaging for 163 low-redshift (v<~7000km/s) galaxies and 3863 artificially redshifted (0.01<~z<~0.25) images of the same galaxies. Comparing results from single-band and multiband techniques, we show that GALFITM significantly improves the extraction of information, particularly from bands with low signal-to-noise ratio (e.g. u and z SDSS bands) when combined with higher signal-to-noise images. We also study systematic trends in the recovered parameters, particularly Sersic index, that appear when one performs measurements of the same galaxies at successively higher redshifts. We argue that it is vital that studies investigating the evolution of galaxy structure are careful to avoid or correct for these biases. The resulting multiband photometric structural parameters for our sample of 163 galaxies are provided. We demonstrate the importance of considering multiband measurements by showing that the Sersic indices of spiral galaxies increase to redder wavelengths, as expected for composite bulge-disc systems. Finally, for the ellipticals in our sample, which should be well represented by single-Sersic models, we compare our measured parameters to those from previous studies.
- ID:
- ivo://CDS.VizieR/J/ApJ/816/53
- Title:
- Multiwavelength obs. of BL Lac in 2012-2013
- Short Name:
- J/ApJ/816/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BL Lac, the eponymous blazar, flared to historically high levels at millimeter, infrared, X-ray, and gamma-ray wavelengths in 2012. We present observations made with Herschel, Swift, NuSTAR, Fermi, the Submillimeter Array, CARMA, and the VLBA in 2012-2013, including three months with nearly daily sampling at several wavebands. We have also conducted an intensive campaign of 30 hr with every-orbit observations by Swift and NuSTAR, accompanied by Herschel, and Fermi observations. The source was highly variable at all bands. Time lags, correlations between bands, and the changing shapes of the spectral energy distributions can be explained by synchrotron radiation and inverse Compton emission from nonthermal seed photons originating from within the jet. The passage of four new superluminal very long baseline interferometry knots through the core and two stationary knots about 4 pc downstream accompanied the high flaring in 2012-2013. The seed photons for inverse Compton scattering may arise from the stationary knots and from a Mach disk near the core where relatively slow-moving plasma generates intense nonthermal radiation. The 95 spectral energy distributions obtained on consecutive days form the most densely sampled, broad wavelength coverage for any blazar. The observed spectral energy distributions and multi-waveband light curves are similar to simulated spectral energy distributions and light curves generated with a model in which turbulent plasma crosses a conical shock with a Mach disk.
- ID:
- ivo://CDS.VizieR/J/ApJ/852/108
- Title:
- Multiwavelength obs. of gamma-ray NOVA Sco 2012
- Short Name:
- J/ApJ/852/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has recently been discovered that some, if not all, classical novae emit GeV gamma-rays during outburst, but the mechanisms involved in the production of gamma-rays are still not well understood. We present here a comprehensive multiwavelength data set-from radio to X-rays-for the most gamma-ray-luminous classical nova to date, V1324 Sco. Using this data set, we show that V1324 Sco is a canonical dusty FeII-type nova, with a maximum ejecta velocity of 2600km/s and an ejecta mass of a few x10^-5^M_{sun}_. There is also evidence for complex shock interactions, including a double-peaked radio light curve which shows high brightness temperatures at early times. To explore why V1324 Sco was so gamma-ray luminous, we present a model of the nova ejecta featuring strong internal shocks and find that higher gamma-ray luminosities result from higher ejecta velocities and/or mass-loss rates. Comparison of V1324 Sco with other gamma-ray-detected novae does not show clear signatures of either, and we conclude that a larger sample of similarly well-observed novae is needed to understand the origin and variation of gamma-rays in novae.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/94
- Title:
- Multiwavelength obs. of GRB 161219B
- Short Name:
- J/ApJ/862/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present detailed multiwavelength observations of GRB 161219B at z=0.1475, spanning the radio to X-ray regimes, and the first Atacama Large Millimeter/submillimeter Array (ALMA) light curve of a {gamma}-ray burst (GRB) afterglow. The centimeter- and millimeter-band observations before 8.5 days require emission in excess of that produced by the afterglow forward shock (FS). These data are consistent with radiation from a refreshed reverse shock (RS) produced by the injection of energy into the FS, signatures of which are also present in the X-ray and optical light curves. We infer a constant- density circumburst environment with an extremely low density, n_0_~3x10^-4^cm^-3^, and show that this is a characteristic of all strong RS detections to date. The Karl G. Lansky Very Large Array (VLA) observations exhibit unexpected rapid variability on roughly minute timescales, indicative of strong interstellar scintillation. The X-ray, ALMA, and VLA observations together constrain the jet break time, t_jet_~32 days, yielding a wide jet opening angle of {theta}_jet_~13{deg}, implying beaming-corrected {gamma}-ray and kinetic energies of E_{gamma}~4.9x10^48^erg and E_K_~1.3x10^50^erg, respectively. Comparing the RS and FS emission, we show that the ejecta are only weakly magnetized, with relative magnetization, R_B_~1, compared to the FS. These direct, multifrequency measurements of a refreshed RS spanning the optical to radio bands highlight the impact of radio and millimeter data in probing the production and nature of GRB jets.
- ID:
- ivo://CDS.VizieR/J/ApJ/881/125
- Title:
- 2014-2018 multiwavelength obs. of PKS 1502+106
- Short Name:
- J/ApJ/881/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The origin of the multiband activities (outbursts/flares) of blazars is still a heavily debated topic. Shock and magnetic reconnection have long been considered as possible triggers of the multiband activities. In this paper, we present an exploration of the origin of multiband activities for a high-redshift (z=1.8385) flat-spectrum radio quasar PKS 1502+106. Utilizing multiband data from radio to {gamma}-ray and optical polarization observations, we investigate two dramatic activities in detail: a {gamma}-ray- dominated outburst in 2015 and an optical-dominated outburst in 2017. Our main results are as follows. (I) A fast {gamma}-ray flare with a flux-doubling timescale as short as 1 hr in 2015 is discovered. Based on the variability timescale, the physical parameters of the flaring region (e.g., minimum Doppler factor, emission region size, etc.) are constrained. At the peak of the flare, the {gamma}-ray spectrum hardens to {Gamma}_{gamma}_=1.82+/-0.04 and exhibits an obvious curvature/break characteristic that is caused by the typical "cooling break." Modeling of multiband spectral energy distributions reveal a very hard electronic energy spectrum with the electronic spectral index of 1.07+/-0.53. This result suggests that this fast {gamma}-ray flare may be triggered by magnetic reconnection. (II) During the outburst in 2017, the degree of optical polarization and optical fluxes showed a very tight correlation. By analyzing the Stokes parameters of polarization observations, our results show that this outburst could be triggered by a transverse shock with a compression ratio of {eta}>2.2, and the magnetic field intensity of the shock emission region is about 0.032G.
- ID:
- ivo://CDS.VizieR/J/A+A/507/1277
- Title:
- Multiwavelength photometry of CDFS X-ray sources
- Short Name:
- J/A+A/507/1277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The co-evolution of host galaxies and the active black holes which reside in their centre is one of the most important topics in modern observational cosmology. Here we present a study of the properties of obscured active galactic nuclei (AGN) detected in the CDFS 1 Ms observation and their host galaxies. We limited the analysis to the MUSIC area, for which deep K-band observations obtained with ISAAC@VLT are available, ensuring accurate identifications of the counterparts of the X-ray sources as well as reliable determination of photometric redshifts and galaxy parameters, such as stellar masses and star formation rates. In particular, we: 1) refined the X-ray/infrared/optical association of 179 sources in the MUSIC area detected in the Chandra observation; 2) studied the host galaxies observed and rest frame colors and properties.
