The exact location of the {gamma}-ray emitting region in blazars is still controversial. In order to attack this problem we present first results of a cross-correlation analysis between radio (11cm to 0.8mm wavelength, F-GAMMA programme) and {gamma}-ray (0.1-300GeV) ~3.5yr light curves of 54 Fermi-bright blazars. We perform a source stacking analysis and estimate significances and chance correlations using mixed source correlations.
The advent of the Fermi gamma-ray space telescope with its superb sensitivity, energy range, and unprecedented capability to monitor the entire 4{pi} sky within less than 2-3 h, introduced a new standard in time domain gamma-ray astronomy. Among several breakthroughs, Fermi has - for the first time - made it possible to investigate, with high cadence, the variability of the broadband spectral energy distribution (SED), especially for active galactic nuclei (AGN). This is necessary for understanding the emission and variability mechanisms in such systems. To explore this new avenue of extragalactic physics the Fermi-GST AGN Multi-frequency Monitoring Alliance (F-GAMMA) programme undertook the task of conducting nearly monthly, broadband radio monitoring of selected blazars, which is the dominant population of the extragalactic gamma-ray sky, from January 2007 to January 2015. In this work we release all the multi-frequency light curves from 2.64 to 43 GHz and first order derivative data products after all necessary post-measurement corrections and quality checks. Along with the demanding task to provide the radio part of the broadband SED in monthly intervals, the F-GAMMA programme was also driven by a series of well-defined fundamental questions immediately relevant to blazar physics. On the basis of the monthly sampled radio SEDs, the F-GAMMA aimed at quantifying and understanding the possible multiband correlation and multi-frequency radio variability, spectral evolution and the associated emission, absorption and variability mechanisms. The location of the gamma-ray production site and the correspondence of structural evolution to radio variability have been among the fundamental aims of the programme. Finally, the programme sought to explore the characteristics and dynamics of the multi-frequency radio linear and circular polarisation. The F-GAMMA ran two main and tightly coordinated observing programmes. The Effelsberg 100 m telescope programme monitoring 2.64, 4.85, 8.35, 10.45, 14.6, 23.05, 32, and 43 GHz, and the IRAM 30 m telescope programme observing at 86.2, 142.3, and 228.9 GHz. The nominal cadence was one month for a total of roughly 60 blazars and targets of opportunity. In a less regular manner the F-GAMMA programme also ran an occasional monitoring with the APEX 12 m telescope at 345 GHz. We only present the Effelsberg dataset in this paper. The higher frequencies data are released elsewhere. The current release includes 155 sources that have been observed at least once by the F-GAMMA programme. That is, the initial sample, the revised sample after the first Fermi release, targets of opportunity, and sources observed in collaboration with a monitoring programme following up on Planck satellite observations. For all these sources we release all the quality-checked Effelsberg multi-frequency light curves. The suite of post-measurement corrections and flagging and a thorough system diagnostic study and error analysis is discussed as an assessment of the data reliability. We also release data products such as flux density moments and spectral indices. The effective cadence after the quality flagging is around one radio SED every 1.3 months. The coherence of each radio SED is around 40 min. The released dataset includes more than 3x104 measurements for some 155 sources over a broad range of frequencies from 2.64 GHz to 43 GHz obtained between 2007 and 2015. The median fractional error at the lowest frequencies (2.64-10.45 GHz) is below 2%. At the highest frequencies (14.6-43 GHz) with limiting factor of the atmospheric conditions, the errors range from 3% to 9%, respectively.
We explore the properties of 24 field early-type galaxies in the redshift range 0.20<z<0.75 down to M_B<=-19.30 in a sample extracted from the FORS Deep Field and the William Herschel Deep Field. Target galaxies were selected on the basis of a combination of luminosity, spectrophotometric type, morphology and photometric redshift or broad-band colours. High signal-to-noise intermediate-resolution spectroscopy has been acquired at the Very Large Telescope, complemented by deep high-resolution imaging with the Advanced Camera for Surveys onboard the HST and additional ground-based multi-band photometry. All galaxy spectra were observed under sub-arcsecond conditions and allow to derive accurate kinematics and stellar population properties of the galaxies. To clarify the low level of star formation detected in some galaxies, we identify the amount of active galactic nuclei (AGN) activity in our sample using archive data of Chandra and XMM-Newton X-ray surveys. None of the galaxies in our sample were identified as secure AGN sources based on their X-ray emission. The rest-frame B and K-band scaling relations of the Faber-Jackson relation and the Fundamental Plane display a moderate evolution for the field early-type galaxies. Lenticular (S0) galaxies feature on average a stronger luminosity evolution and bluer rest-frame colours which can be explained that they comprise more diverse stellar populations compared to elliptical galaxies. The evolution of the FP can be interpreted as an average change in the dynamical (effective) mass-to-light ratio of our galaxies as <{Delta}log(M/L_B_)/z>=-0.74+/-0.08. The M/L evolution of these field galaxies suggests a continuous mass assembly of field early-type galaxies during the last 5Gyr, that gets support by recent studies of field galaxies up to z~1. Independent evidence for recent star formation activity is provided by spectroscopic (OII emission, Hdelta) and photometric (rest-frame broad-band colors) diagnostics. Based on the Hdelta absorption feature we detect a weak residual star formation for galaxies that accounts for 5%-10% in the total stellar mass of these galaxies. The co-evolution in the luminosity and mass of our galaxies favours a downsizing formation process. We find some evidence that our galaxies experienced a period of star formation quenching, possible triggered by AGN activity that is in good agreement with recent results on both observational and theoretical side.
We present the final analysis of the European Large Area Infrared Space Observatory (ISO) Survey (ELAIS) 15-{mu}m observations, carried out with the ISO Camera (ISOCAM) instrument on board the ISO. The data-reduction method, known as the Lari Method, is based on a mathematical model of the behaviour of the detector and was specifically designed for the detection of faint sources in ISOCAM/ISO Photopolarimeter (ISOPHOT) data. The method is fully interactive and leads to very reliable and complete source lists. The resulting catalogue includes 1923 sources detected with signal-to-noise ratio of >5 in the 0.5-100mJy flux range and over an area of 10.85deg^2^ split into four fields, making it the largest non-serendipitous extragalactic source catalogue obtained to date from the ISO data.
We have examined the compact structure in 250 flat-spectrum extragalactic radio sources using interferometric fringe visibilities obtained with the Very Long Baseline Array (VLBA) at 15GHz. With projected baselines out to 440M{lambda}, we are able to investigate source structure on typical angular scales as small as 0.05mas.
We investigate star formation and dust heating in the compact far-infrared (FIR) bright sources detected in the Herschel maps of M83. We use the source extraction code GETSOURCES to detect and extract sources in the FIR, as well as their photometry in the mid-infrared and H{alpha}. By performing infrared spectral energy distribution fitting and applying an H{alpha}-based star formation rate (SFR) calibration, we derive the dust masses and temperatures, SFRs, gas masses and star formation efficiencies (SFEs). The detected sources lie exclusively on the spiral arms and represent giant molecular associations, with gas masses and sizes of 106-108M{sun} and 200-300pc, respectively. The inferred parameters show little to no radial dependence and there is only a weak correlation between the SFRs and gas masses, which suggests that more massive clouds are less efficient at forming stars. Dust heating is mainly due to local star formation. However, although the sources are not optically thick, the total intrinsic young stellar population luminosity can almost completely account for the dust luminosity. This suggests that other radiation sources also contribute to the dust heating and approximately compensate for the unabsorbed fraction of UV light.
FIR data of IR-bright dust-obscured galaxies (DOGs)
Short Name:
J/ApJ/840/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the star-forming activity of a sample of infrared (IR)-bright dust-obscured galaxies (DOGs) that show an extreme red color in the optical and IR regime, (i-[22])_AB_>7.0. Combining an IR-bright DOG sample with the flux at 22{mu}m>3.8mJy discovered by Toba & Nagao (2016ApJ...820...46T) with the IRAS faint source catalog version 2 and AKARI far-IR (FIR) all-sky survey bright source catalog version 2, we selected 109 DOGs with FIR data. For a subsample of seven IR-bright DOGs with spectroscopic redshifts (0.07<z<1.0) that were obtained from the literature, we estimated their IR luminosity, star formation rate (SFR), and stellar mass based on the spectral energy distribution fitting. We found that (1) the WISE 22{mu}m luminosity at the observed frame is a good indicator of IR luminosity for IR-bright DOGs and (2) the contribution of the active galactic nucleus to IR luminosity increases with IR luminosity. By comparing the stellar mass and SFR relation for our DOG sample and the literature, we found that most of the IR-bright DOGs lie significantly above the main sequence of star-forming galaxies at similar redshift, indicating that the majority of IRAS- or AKARI-detected IR-bright DOGs are starburst galaxies.
We present a Ks-selected catalog, dubbed FIREWORKS, for the Chandra Deep Field-South (CDF-S) containing photometry in the U_38_, B_435_, B, V, V_606_, R, i_775_, I, z_850_, J, H, Ks, [3.6um], [4.5um], [5.8um], [8.0um], and MIPS [24um] bands. The imaging has a typical K^tot^_s,AB_ limit of 24.3mag (5{sigma}) and coverage over 113arcmin^2^ in all bands and 138arcmin^2^ in all bands but H. We cross-correlate our catalog with the 1Ms X-ray catalog by Giacconi et al. (2002, Cat. J/ApJS/139/369) and with all available spectroscopic redshifts to date. We find and explain systematic differences in a comparison with the "z_850_+Ks"-selected GOODS-MUSIC catalog (Cat. J/A+A/449/951) that covers ~90% of the field. We exploit the U_38_-to-24um photometry to determine which Ks-selected galaxies at 1.5<z<2.5 have the brightest total IR luminosities and which galaxies contribute most to the integrated total IR emission. The answer to both questions is that red galaxies are dominating in the IR. This is true no matter whether color is defined in the rest-frame UV, optical, or optical-near-IR. We do find, however, that among the reddest galaxies in the rest-frame optical, there is a population of sources with only little mid-IR emission, suggesting a quiescent nature.
We present Herschel (PACS and SPIRE) far-infrared (FIR) photometry of a complete sample of z>1 3CR sources, from the Herschel guaranteed time project The Herschel Legacy of distant radio-loud AGN. Combining these with existing Spitzer photometric data, we perform an infrared (IR) spectral energy distribution (SED) analysis of these landmark objects in extragalactic research to study the star formation in the hosts of some of the brightest active galactic nuclei (AGN) known at any epoch. Accounting for the contribution from an AGN-powered warm dust component to the IR SED, about 40% of our objects undergo episodes of prodigious, ULIRG-strength star formation, with rates of hundreds of solar masses per year, coeval with the growth of the central supermassive black hole. Median SEDs imply that the quasar and radio galaxy hosts have similar FIR properties, in agreement with the orientation-based unification for radio-loud AGN. The star-forming properties of the AGN hosts are similar to those of the general population of equally massive non-AGN galaxies at comparable redshifts, thus there is no strong evidence of universal quenching of star formation (negative feedback) within this sample. Massive galaxies at high redshift may be forming stars prodigiously, regardless of whether their supermassive black holes are accreting or not.
A Catalogue of galaxies with UV-continuum (Markarian galaxies) detected during the First Byurakan Survey (FBS) is presented. The purpose of the Survey was to search for peculiar faint extragalactic objects with UV-excess radiation and to study them. The procedure of observations and processings, the Survey areas, the object selection and classification criteria and also several selection effects are described. The Catalogue contains the following initial data on all the objects: the precise coordinates, visual magnitudes, angular sizes, redshifts and classification types. The observational results of slit spectra, UBV-photometry, IR-photometry (IRAS data), morphology and some other data are also included into the Catalogue. While compiling the Catalogue the authors introduced some necessary corrections in the data of the earlier published lists on galaxies with UV-continuum. In addition we included the objects with numbers 1501-1515. In most cases they are well-known Seyfert galaxies omitted by the authors in the lists, but detected on the plates. 41 objects from our lists are not included into the Catalogue, since they are either stars of our Galaxy or star projections on the galaxies. The Catalogue presents the largest homogeneous sample of AGN of different types on the northern sky for bright objects (<16.0). Up to the middle of 1987 the redshifts were measured for 1459 out of 1469 objects of the Catalogue.