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- ID:
- ivo://CDS.VizieR/J/AJ/139/1438
- Title:
- SED and age estimates of 104 M31 globular clusters
- Short Name:
- J/AJ/139/1438
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometry of 104 M31 globular clusters (GCs) and GC candidates in 15 intermediate-band filters of the Beijing-Arizona-Taiwan-Connecticut photometric system. The GCs and GC candidates were selected from the Revised Bologna Catalog (v.3.5). We obtain the cluster ages by comparing the photometric data with up-to-date theoretical synthesis models. The photometric data used are Galaxy Evolution Explorer far- and near-ultraviolet and Two Micron All Sky Survey near-infrared JHKs magnitudes, combined with optical photometry. The ages of our sample clusters cover a large range, although most clusters are younger than 10Gyr. Combined with the ages obtained in our series of previous papers focusing on the M31 GC system, we present the full M31 GC age distribution.
- ID:
- ivo://CDS.VizieR/J/ApJ/786/59
- Title:
- SED fitting results of HETDEX pilot survey
- Short Name:
- J/ApJ/786/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use broadband photometry extending from the rest-frame UV to the near-IR to fit the individual spectral energy distributions of 63 bright (L(Ly{alpha})>10^43^ erg/s) Ly{alpha} emitting galaxies (LAEs) in the redshift range 1.9<z<3.6. We find that these LAEs are quite heterogeneous, with stellar masses that span over three orders of magnitude, from 7.5<log M/M_{sun}_<10.5. Moreover, although most LAEs have small amounts of extinction, some high-mass objects have stellar reddenings as large as E(B-V)~0.4. Interestingly, in dusty objects the optical depths for Ly{alpha} and the UV continuum are always similar, indicating that Ly{alpha} photons are not undergoing many scatters before escaping their galaxy. In contrast, the ratio of optical depths in low-reddening systems can vary widely, illustrating the diverse nature of the systems. Finally, we show that in the star-formation-rate-log-mass diagram, our LAEs fall above the "main-sequence" defined by z~3 continuum selected star-forming galaxies. In this respect, they are similar to submillimeter-selected galaxies, although most LAEs have much lower mass.
- ID:
- ivo://CDS.VizieR/J/AJ/143/125
- Title:
- SED of 113 dust-obscured galaxies at z~2
- Short Name:
- J/AJ/143/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dust-obscured galaxies (DOGs) are a subset of high-redshift (z~2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L_IR_>10^12^L_{sun}_). We present new far-infrared photometry, at 250, 350, and 500{mu}m (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10^11.6^L_{sun}_<L_IR_(8-1000{mu}m)<10^13.6^L_{sun}_. 90% of the Herschel-detected DOGs in this sample are ULIRGs and 30% have L_IR_>10^13L{sun}. The rest-frame near-IR (1-3{mu}m) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths.
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/2034
- Title:
- SED of K+A galaxies from UV to mid-IR
- Short Name:
- J/MNRAS/431/2034
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectrum synthesis fits to 808 K+A galaxies selected from the Sloan Digital Sky Survey (SDSS) and population synthesis of their spectral energy distributions, extending from the far-UV (0.15{mu}m) to the mid-IR (22{mu}m), based on the results of STARLIGHT code fitting to the SDSS spectra. Our modelling shows that K+A galaxies have undergone a large starburst, involving a median 50% of their present stellar masses, superposed over an older stellar population. The metal abundance of the intermediate-age stars shows that star formation did not take place in pristine gas, but was part of a dramatic increase in the star formation rates for originally gas-rich objects. We find no evidence for ongoing QSO activity in the UV, which is well modelled by the emission of intermediate-age stars. We use K+A galaxies as local counterparts of high-redshift objects to test for the presence of thermally pulsing asymptotic giant branch (TP-AGB) stars in similarly aged populations and find no excess in the infrared due to emission from such stars, arguing that more distant galaxies are indeed old and massive at their redshift. All of our galaxies show significant excesses in the mid-IR compared to the light from their stars. We fit this ad hoc with a 300K blackbody. Possible sources include TP-AGB stars, obscured young star clusters and hidden AGNs, heating a significant dust component.
- ID:
- ivo://CDS.VizieR/J/ApJ/666/806
- Title:
- SED of Spitzer quasars (QUEST)
- Short Name:
- J/ApJ/666/806
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second paper studying the QSOs in the Spitzer QUEST sample. Previously we presented new PAH measurements and argued that most of the observed far-infrared (FIR) radiation is due to star-forming activity. Here we present spectral energy distributions (SEDs) by supplementing our data with optical, NIR, and FIR observations. We define two subgroups, of "weak FIR" and "strong FIR" QSOs, and a third group of FIR nondetections. Assuming a starburst origin for the FIR, we obtain "intrinsic" active galactic nucleus (AGN) SEDs by subtracting a starburst template from the mean SEDs. The resulting SEDs are remarkably similar for all groups.
- ID:
- ivo://CDS.VizieR/J/MNRAS/495/1853
- Title:
- SED-selected AGN in the VIPERS field
- Short Name:
- J/MNRAS/495/1853
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The detection of X-ray emission constitutes a reliable and efficient tool for the selection of active galactic nuclei (AGNs), although it may be biased against the most heavily absorbed AGNs. Simple mid-infrared (IR) broad-band selection criteria identify a large number of luminous and absorbed AGNs, yet again host contamination could lead to non-uniform and incomplete samples. Spectral energy distribution (SED) decomposition is able to decouple the emission from the AGN versus that from star-forming regions, revealing weaker AGN components. We aim to identify the obscured AGN population in the VIMOS Public Extragalactic Redshift Survey in the Canada-France-Hawaii Telescope Legacy Survey W1 field through SED modelling. We construct SEDs for 6860 sources and identify 160 AGNs at a high confidence level using a Bayesian approach. Using optical spectroscopy, we confirm the nature of ~85 per cent of the AGNs. Our AGN sample is highly complete (~92 per cent) compared to mid-IR colour-selected AGNs, including a significant number of galaxy-dominated systems with lower luminosities. In addition to the lack of X-ray emission (80 per cent), the SED fitting results suggest that the majority of the sources are obscured. We use a number of diagnostic criteria in the optical, IR, and X-ray regimes to verify these results. Interestingly, only 35 per cent of the most luminous mid-IR-selected AGNs have X-ray counterparts suggesting strong absorption. Our work emphasizes the importance of using SED decomposition techniques to select a population of type II AGNs, which may remain undetected by either X-ray or IR colour surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/514/A11
- Title:
- SEDs in ADFS (AKARI Deep Field South)
- Short Name:
- J/A+A/514/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the nature and properties of far-infrared (FIR) sources in the AKARI Deep Field South (ADF-S). We performed an extensive search for the counterparts to 1000 ADF-S objects brighter than 0.0301Jy in the WIDE-S (90um) AKARI band in the public databases (NED and SIMBAD). We analyzed the properties of the resulting sample: statistics of the identified objects, quality of position determination of the ADF-S sources, their number counts, redshift distribution, and comparison of morphological types, when the corresponding information was available. We performed a simplified analysis of the clustering properties of the ADF-S sources and compiled spectral energy distributions (SEDs) of objects with the highest quality photometry, using three different models. Among 1000 investigated ADF-S sources, 545 were identified with sources at other wavelengths in public databases. From them, 518 are known galaxies and 343 of these were previously known as infra-red sources. Among the remaining sources, there are two quasars and both infrared and radio sources of unknown origin. Among six stellar identifications, at least five are probably the effect of contamination. We measured the redshifts of 48 extragalactic objects and determined the morphological types of 77 galaxies. We present SED models of 47 sources with sufficiently good photometric data. Conclusions: We conclude that the bright FIR point sources observed in the ADF-S are mostly nearby galaxies. Their properties are very similar to the properties of the local population of optically bright galaxies, except for unusually high ratio of peculiar or interacting objects and a lower percentage of elliptical galaxies. The percentage of lenticular galaxies is the same as in the optically bright population, which suggests that galaxies of this type may frequently contain a significant amount of cool dust. It is possible that source confusion plays a significant role in more than 34% of measurements. The SEDs correspond to a variety of galaxy types, from very actively star forming to very quiescent. The AKARI long wavelength bands data have enabled us to determine for the first time that these galaxies are objects with very cool dust.
- ID:
- ivo://CDS.VizieR/J/ApJ/684/136
- Title:
- SEDs of ELAIS-S1 mid-IR sources
- Short Name:
- J/ApJ/684/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the broadband SEDs of the largest available highly complete (72%) spectroscopic sample of MIR-selected galaxies and AGNs at intermediate redshift. The sample contains 203 extragalactic sources from the 15um ELAIS-SWIRE survey, all with measured spectroscopic redshift. Most of these sources have full multiwavelength coverage from the FUV (GALEX) to the FIR (Spitzer) and lie in the redshift range 0.1<z<1.3. This large sample allows us for the first time to characterize the spectral properties of sources responsible for the strong evolution observed in the MIR. Based on SED-fitting, we have classified the MIR sources, identifying AGN signatures in about 50% of them. This fraction is significantly higher than that derived from optical spectroscopy (~29%) and is due in particular to the identification of AGN activity in objects spectroscopically classified as galaxies (the spectroscopic classification may be somewhat unreliable because of host galaxy dilution in the optical). It is likely that in most of our objects, the AGN is either obscured or low luminosity, and thus dominates the energetic output only in the MIR, showing up just in the range where the host galaxy SED has a minimum. The fraction of AGNs strongly depends on flux density, with that derived through the SED-fitting about 20% at S_15um_~0.5-1mJy and gradually increasing to 100% at S_15um_>10mJy, while that obtained from optical spectroscopy is never >30%, even at higher flux densities.
- ID:
- ivo://CDS.VizieR/J/ApJ/738/69
- Title:
- SEDs of galaxies at 3.8<z<5 in GOODS
- Short Name:
- J/ApJ/738/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present evidence for strong H{alpha} emission in galaxies with spectroscopic redshifts in the range of 3.8<z<5.0 over the Great Observatories Origins Deep Survey fields. Among 74 galaxies detected in the Spitzer IRAC 3.6 and 4.5um bands, more than 70% of the galaxies show clear excess at 3.6um compared to the expected flux density from stellar continuum only. We provide evidence that this 3.6um excess is due to H{alpha} emission redshifted into the 3.6um band, and classify these 3.6um excess galaxies to be H{alpha} emitter (HAE) candidates. The selection of HAE candidates using an excess in broadband filters is sensitive to objects whose rest-frame H{alpha} equivalent width (EW) is larger than 350{AA}. The H{alpha} inferred star formation rates (SFRs) of the HAEs range between 20 and 500M_{sun}_/yr and are a factor of ~6 larger than SFRs inferred from the UV continuum. The ratio between the H{alpha} luminosity and UV luminosity of HAEs is also on average larger than that of local starbursts.
