- ID:
- ivo://CDS.VizieR/J/A+A/570/A29
- Title:
- TBOSS Survey I: Herschel/PACS
- Short Name:
- J/A+A/570/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With Herschel PACS 134 low mass members of the Taurus star-forming region spanning the M4-L0 spectral type range and covering the transition from low mass stars to brown dwarfs were observed. Combining the new Herschel results with other programs, a total of 150 of the 154 M4-L0 Taurus members members have observations with Herschel. Among the 150 targets, 70um flux densities were measured for 7 of the 7 Class I objects, 48 of the 67 Class II members, and 3 of the 76 Class III targets. For the detected Class II objects, the median 70um flux density level declines with spectral type, however, the distribution of excess relative to central object flux density does not change across the stellar/substellar boundary in the M4-L0 range. Connecting the 70um TBOSS values with the results from K0-M3 Class II members results in the first comprehensive census of far-IR emission across the full mass spectrum of the stellar and substellar population of a star-forming region, and the median flux density declines with spectral type in a trend analogous to the flux density decline expected for the central objects. Based on an initial exploration of the impact of different physical parameters; inclination, scale height and flaring have the largest influence on the PACS flux densities. From the 24um to 70um spectral index of the SEDs, 5 new candidate transition disks were identified. The steep 24um to 70um slope for a subset of 8 TBOSS targets may be an indication of truncated disks in these systems. Two examples of mixed pair systems that include secondaries with disks were measured. Finally, comparing the TBOSS results with a Herschel study of Ophiuchus brown dwarfs reveals a lower fraction of disks around the Taurus substellar population.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/493/2438
- Title:
- The 2BIGB gamma-ray blazars catalog
- Short Name:
- J/MNRAS/493/2438
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the results of a {gamma}-ray likelihood analysis over all the extreme and high synchrotron peak blazars (EHSP and HSP) from the 3HSP catalogue. We investigate 2013 multifrequency positions under the eyes of Fermi Large Area Telescope, considering 11yr of observations in the energy range between 500MeV and 500GeV, which results in 1160 {gamma}-ray signatures detected down to the TS=9 threshold. The detections include 235 additional sources concerning the Fermi Large Area Telescope Fourth Source Catalog (4FGL), all confirmed via high-energy TS (Test Statistic) maps, and represent an improvement of ~25% for the number of EHSP and HSP currently described in {gamma}-rays. We build the {gamma}-ray spectral energy distribution (SED) for all the 1160 2BIGB sources, plot the corresponding {gamma}-ray logN-logS, and measure their total contribution to the extragalactic gamma-ray background, which reaches up to ~33% at 100GeV. Also, we show that the {gamma}-ray detectability improves according to the synchrotron peak flux as represented by the figure of merit parameter, and note that the search for TeV peaked blazars may benefit from considering HSP and EHSP as a whole, instead of EHSPs only. The 2BIGB acronym stands for 'Second Brazil-ICRANet Gamma-ray Blazars' catalogue.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/5
- Title:
- The Herschel Orion Protostar Survey (HOPS): SEDs
- Short Name:
- J/ApJS/224/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present key results from the Herschel Orion Protostar Survey (HOPS): spectral energy distributions (SEDs) and model fits of 330 young stellar objects, predominantly protostars, in the Orion molecular clouds. This is the largest sample of protostars studied in a single, nearby star formation complex. With near-infrared photometry from 2MASS, mid- and far-infrared data from Spitzer and Herschel, and submillimeter photometry from APEX, our SEDs cover 1.2-870{mu}m and sample the peak of the protostellar envelope emission at ~100{mu}m. Using mid-IR spectral indices and bolometric temperatures, we classify our sample into 92 Class 0 protostars, 125 Class I protostars, 102 flat-spectrum sources, and 11 Class II pre-main-sequence stars. We implement a simple protostellar model (including a disk in an infalling envelope with outflow cavities) to generate a grid of 30400 model SEDs and use it to determine the best-fit model parameters for each protostar. We argue that far-IR data are essential for accurate constraints on protostellar envelope properties. We find that most protostars, and in particular the flat-spectrum sources, are well fit. The median envelope density and median inclination angle decrease from Class 0 to Class I to flat-spectrum protostars, despite the broad range in best-fit parameters in each of the three categories. We also discuss degeneracies in our model parameters. Our results confirm that the different protostellar classes generally correspond to an evolutionary sequence with a decreasing envelope infall rate, but the inclination angle also plays a role in the appearance, and thus interpretation, of the SEDs.
- ID:
- ivo://CDS.VizieR/J/ApJS/187/64
- Title:
- The simultaneous optical-to-X-ray SED of AGNs
- Short Name:
- J/ApJS/187/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report Swift observations of a sample of 92 bright soft X-ray selected active galactic nuclei (AGNs). This sample represents the largest number of AGNs observed to study the spectral energy distribution (SED) of AGNs with simultaneous optical/UV and X-ray data. The principal motivation of this study is to understand the SEDs of AGNs in the optical/UV to X-ray regime and to provide bolometric corrections which are important in determining the Eddington ratio L/L_Edd_. In particular, we rigorously explore the dependence of the UV-EUV contribution to the bolometric correction on the assumed EUV spectral shape. We find strong correlations of the spectral slopes {alpha}_X_ and {alpha}_UV_ with L/L_Edd_.
- ID:
- ivo://CDS.VizieR/J/MNRAS/456/790
- Title:
- TP-AGB stars contribution in SFR
- Short Name:
- J/MNRAS/456/790
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the debated contribution from thermally pulsing asymptotic-giant-branch (TP-AGB) stars in evolutionary population synthesis models. We investigate the spectral energy distributions (SEDs) of a sample of 51 spectroscopically confirmed, high-z (1.3<z_spec_<2.7), galaxies using three evolutionary population synthesis models with strong, mild and light TP-AGB. Our sample is the largest of spectroscopically confirmed galaxies on which such models are tested so far. Galaxies were selected as passive, but we model them using a variety of star formation histories in order not to be dependent on this pre-selection. We find that the observed SEDs are best fitted with a significant contribution of TP-AGB stars or with substantial dust attenuation. Without including reddening, TP-AGB-strong models perform better and deliver solutions consistent within 1{sigma} from the best-fitted ones in the vast majority of cases. Including reddening, all models perform similarly. Using independent constraints from observations in the mid- and far-IR, we show that low/negligible dust attenuation, i.e. E(B-V)<~0.05, should be preferred for the SEDs of passively selected galaxies. Given that TP-AGB-light models give systematically older ages for passive galaxies, we suggest number counts of passive galaxies at higher redshifts as a further test to discriminate among stellar population models.
- ID:
- ivo://CDS.VizieR/J/A+A/647/A195
- Title:
- Unknown active galactic nuclei study
- Short Name:
- J/A+A/647/A195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We collect data at all frequencies for the new sources classified as unknown active galactic nuclei (AGNs) in the latest Burst Alert Telescope all-sky hard X-ray catalog. Focusing on the 36 sources with measured redshift, we compute their spectral energy distribution (SED) from radio to {gamma}-rays with the aim to classify these objects. We apply emission models that attempt to reproduce the obtained SEDs, including: (i) a standard thin accretion disk together with an obscuring torus and a X-ray corona; (ii) a two temperature thick advection-dominated flow; (iii) an obscured AGN model, accounting for absorption along the line of sight at kiloelectronvolt energies and in the optical band; and (iv) a phenomenological model to describe the jet emission in blazar-like objects. We integrate the models with the SWIRE template libraries to account for the emission of the host galaxy. For every source we found a good agreement between data and our model. Considering that the sources were selected in the hard X-ray band, which is rather unaffected by absorption, we expected and found a large fraction of absorbed radio-quiet AGNs (31 out of 36) and some additional rare radio-loud sources (5 out of 36), since the jet emission in hard X-rays is important for aligned jets owing to the boost produced by the beaming effect. With our work we can confirm the hypothesis that a number of galaxies, whose optical spectra lack AGN emission features, host an obscured active nucleus. The approach we used proved to be efficient in rapidly identifying objects, which commonly used methods were not able to classify.
- ID:
- ivo://CDS.VizieR/J/ApJS/243/15
- Title:
- WERGS. II. SED fitting with optical, IR & radio data
- Short Name:
- J/ApJS/243/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present physical properties of radio galaxies (RGs) with f_1.4GHz_>1mJy discovered by Subaru Hyper Suprime-Cam (HSC) and Very Large Array Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. For 1056 FIRST RGs at 0<z<=1.7 with HSC counterparts in about 100deg^2^, we compiled multi-wavelength data of optical, near-infrared (IR), mid-IR, far-IR, and radio (150MHz). We derived their color excess (E(B-V)_*_), stellar mass, star formation rate (SFR), IR luminosity, the ratio of IR and radio luminosity (q_IR_), and radio spectral index ({alpha}_radio_) that are derived from the spectral energy distribution (SED) fitting with CIGALE. We also estimated Eddington ratio based on stellar mass and integration of the best-fit SEDs of active galactic nucleus (AGN) component. We found that E(B-V)_*_, SFR, and IR luminosity clearly depend on redshift while stellar mass, q_IR_, and {alpha}_radio_ do not significantly depend on redshift. Since optically faint (i_AB_>=21.3) RGs that are newly discovered by our RG survey tend to be high redshift, they tend to not only have a large dust extinction and low stellar mass but also have high SFR and AGN luminosity, high IR luminosity, and high Eddington ratio compared with optically bright ones. The physical properties of a fraction of RGs in our sample seem to differ from a classical view of RGs with massive stellar mass, low SFR, and low Eddington ratio, demonstrating that our RG survey with HSC and FIRST provides us curious RGs among entire RG population.
- ID:
- ivo://CDS.VizieR/J/ApJ/805/90
- Title:
- WISE ELIRGs and comparison with QSOs
- Short Name:
- J/ApJ/805/90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 20 Wide-field Infrared Survey Explorer (WISE)-selected galaxies with bolometric luminosities L_bol_>10^14^L_{sun}_, including five with infrared luminosities L_IR_{equiv}L_(rest8-1000{mu}m)_>10^14^L_{sun}_. These "extremely luminous infrared galaxies", or ELIRGs, were discovered using the "W1W2-dropout" selection criteria which requires marginal or non-detections at 3.4 and 4.6{mu}m (W1 and W2, respectively) but strong detections at 12 and 22{mu}m in the WISE survey. Their spectral energy distributions are dominated by emission at rest-frame 4-10{mu}m, suggesting that hot dust with T_d_~450K is responsible for the high luminosities. These galaxies are likely powered by highly obscured active galactic nuclei (AGNs), and there is no evidence suggesting these systems are beamed or lensed. We compare this WISE-selected sample with 116 optically selected quasars that reach the same L_bol_ level, corresponding to the most luminous unobscured quasars in the literature. We find that the rest-frame 5.8 and 7.8{mu}m luminosities of the WISE-selected ELIRGs can be 30%-80% higher than that of the unobscured quasars. The existence of AGNs with L_bol_>10^14^L_{sun}_ at z>3 suggests that these supermassive black holes are born with large mass, or have very rapid mass assembly. For black hole seed masses ~10^3^M_{sun}_, either sustained super-Eddington accretion is needed, or the radiative efficiency must be <15%, implying a black hole with slow spin, possibly due to chaotic accretion.
- ID:
- ivo://CDS.VizieR/J/A+A/539/A48
- Title:
- XMM AGN optical-UV luminosities
- Short Name:
- J/A+A/539/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Active galactic nuclei (AGN) emit radiation over a wide range of wavelengths, with a peak of emission in the far-UV region of the electromagnetic spectrum, a spectral region that is historically difficult to observe. Using optical, GALEX UV, and XMM-Newton data we derive the spectral energy distribution (SED) from the optical/UV to X-ray regime of a sizeable sample of AGN. The principal motivation is to investigate the relationship between the optical/UV emission and the X-ray emission and provide bolometric corrections to the hard X-ray (2-10keV) energy range, k_bol_, the latter being a fundamental parameter in current physical cosmology.
- ID:
- ivo://CDS.VizieR/J/ApJS/226/20
- Title:
- X-ray, opt. & radio SEDs of Fermi blazars
- Short Name:
- J/ApJS/226/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, multiwavelength data are compiled for a sample of 1425 Fermi blazars to calculate their spectral energy distributions (SEDs). A parabolic function, log({nu}F_{nu}_)=P_1_(log{nu}-P_2_)^2^+P_3_, is used for SED fitting. Synchrotron peak frequency (log{nu}_p_), spectral curvature (P_1_), peak flux ({nu}_p_F_{nu}p_), and integrated flux ({nu}F_{nu}_) are successfully obtained for 1392 blazars (461 flat-spectrum radio quasars [FSRQs], 620 BL Lacs [BLs], and 311 blazars of uncertain type [BCUs]; 999 sources have known redshifts). Monochromatic luminosity at radio 1.4GHz, optical R band, X-ray at 1keV and {gamma}-ray at 1GeV, peak luminosity, integrated luminosity, and effective spectral indices of radio to optical ({alpha}_RO_) and optical to X-ray ({alpha}_OX_) are calculated. The "Bayesian classification" is employed to log{nu}_p_ in the rest frame for 999 blazars with available redshift, and the results show that three components are enough to fit the log{nu}_p_ distribution; there is no ultra-high peaked subclass. Based on the three components, the subclasses of blazars using the acronyms of Abdo+ (2010, J/ApJ/716/30) are classified, and some mutual correlations are also studied.
