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- ID:
- ivo://CDS.VizieR/J/ApJ/869/4
- Title:
- Far-infrared SED measurements of massive galaxies
- Short Name:
- J/ApJ/869/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive Population II galaxies undergoing the first phase of vigorous star formation after the initial Population III stage should have high energy densities and silicate-rich interstellar dust. We have modeled the resulting far-infrared spectral energy distributions (SEDs), demonstrating that they are shifted substantially to bluer ("warmer") wavelengths relative to the best fitting ones at z~3, and with strong outputs in the 10-40{mu}m range. When combined with a low level of emission by carbon dust, their SEDs match that of Haro 11, a local moderately low-metallicity galaxy undergoing a very young and vigorous starburst that is likely to approximate the relevant conditions in young Population II galaxies. We expect to see similar SEDs at high redshifts (z>~5) given the youth of galaxies at this epoch. In fact, we find a progression with redshift in observed galaxy SEDs, from those resembling local ones at 2<~z<4 to a closer resemblance with Haro 11 at 5<~z<7. In addition to the insight on conditions in high-redshift galaxies, this result implies that estimates of the total infrared luminosities at z~6 based on measurements near {lambda}~1mm can vary by factors of 2-4, depending on the SED template used. Currently popular modified blackbodies or local templates can result in significant underestimates compared with the preferred template based on the SED of Haro 11.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A60
- Title:
- F-GAMMA 2.64-43GHz radio data over 2007-2015
- Short Name:
- J/A+A/626/A60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/849/63
- Title:
- FIR-mm data of YSOs in star-forming regions
- Short Name:
- J/ApJ/849/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Far-infrared and (sub)millimeter fluxes can be used to study dust in protoplanetary disks, the building blocks of planets. Here, we combine observations from the Herschel Space Observatory with ancillary data of 284 protoplanetary disks in the Taurus, Chamaeleon I, and Ophiuchus star-forming regions, covering from the optical to mm/cm wavelengths. We analyze their spectral indices as a function of wavelength and determine their (sub)millimeter slopes when possible. Most disks display observational evidence of grain growth, in agreement with previous studies. No correlation is found between other tracers of disk evolution and the millimeter spectral indices. A simple disk model is used to fit these sources, and we derive posterior distributions for the optical depth at 1.3mm and 10au, the disk temperature at this same radius, and the dust opacity spectral index {beta}. We find the fluxes at 70{mu}m to correlate strongly with disk temperatures at 10au, as derived from these simple models. We find tentative evidence for spectral indices in Chamaeleon I being steeper than those of disks in Taurus/Ophiuchus, although more millimeter observations are needed to confirm this trend and identify its possible origin. Additionally, we determine the median spectral energy distribution of each region and find them to be similar across the entire wavelength range studied, possibly due to the large scatter in disk properties and morphologies.
- ID:
- ivo://CDS.VizieR/J/A+A/564/A111
- Title:
- Galactic plane dust temperature maps with Herschel
- Short Name:
- J/A+A/564/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dust grains absorb the interstellar far ultra-violet and visible photons and re-emit them in far-infrared (FIR) wavebands. The dust FIR continuum can be predicted by a grid of models using various values of the interstellar radiation field. We analyze the dust continuum emission in two Hi-GAL science-demonstration phase (SDP) fields using both the radiative transfer code, Cloudy, and the DustEM dust model, to explore the effect of radiative transfer on dust temperature. The 500um sub-millimeter excess emission and the very small grain (VSG) contribution to the 70um intensity are investigated by spectral energy distribution (SED) fitting using the Cloudy model.
- ID:
- ivo://CDS.VizieR/J/AJ/121/2895
- Title:
- HDF-N Caltech faint galaxy redshift survey. XIII.
- Short Name:
- J/AJ/121/2895
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce a new empirical function for modeling the spectral energy distributions (SEDs) of galaxies. We apply it to a sample of 590 galaxies in the region of the Hubble Deep Field (HDF) with z<1.5 using multicolor photometry with wide wavelength coverage combined with spectroscopic redshifts from our 93% complete R-selected redshift survey there.
- ID:
- ivo://CDS.VizieR/J/MNRAS/409/2
- Title:
- 86 Herschel sources SED model parameters
- Short Name:
- J/MNRAS/409/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectral energy distributions (SEDs) for 86 Herschel sources detected at 5{sigma} at 250, 350 and 500um in the HerMES SWIRE-Lockman field. We explore whether existing models for starbursts, quiescent star-forming galaxies and active galactic nucleus dust tori are able to model the full range of SEDs measured with Herschel. We find that while many galaxies (~56 per cent) are well fitted with the templates used to fit IRAS, Infrared Space Observatory (ISO) and Spitzer sources, for about half the galaxies two new templates are required: quiescent ('cirrus') models with colder (10-20K) dust and a young starburst model with higher optical depth than Arp 220. Predictions of submillimetre fluxes based on model fits to 4.5-24um data agree rather poorly with the observed fluxes, but the agreement is better for fits to 4.5-70um data. Herschel galaxies detected at 500um tend to be those with the highest dust masses.
- ID:
- ivo://CDS.VizieR/J/A+A/555/A64
- Title:
- Identifying gaps in flaring Herbig Ae/Be disks
- Short Name:
- J/A+A/555/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolution of protoplanetary disks towards mature planetary systems is expected to include the formation of 'gaps' in the disk possibly due to planet formation. We studied the disks of four key intermediate mass (Herbig Ae/Be) stars in order to understand the influence of gaps to their observational appearance. We investigate mid-infrared images and perform radiative transfer modeling to examine the radial distribution of dust and PAHs. Our solutions constrain the sizes of the gaps. For one particular object, HD 97048, this is the first detection of a disk gap. The large gaps deplete the entire population of silicate particles with temperatures suitable for prominent mid-infrared feature emission, while small carbonaceous grains and PAHs can still show prominent emission at mid-infrared wavelengths. The absence of silicate emission features is due to the presence of large gaps in the critical temperature regime. Our results suggest that many, if not all Herbig disks with weak or no silicate features in the spectrum are disks with large gaps and can be characterized as (pre-)transitional. We conclude that the evolution of Herbig stars follows two different paths. Competition between the timescales of inner versus outer disk evolution determine whether young protoplanetary disks evolve into transitional disks (due to planet formation in the inner disk) or into flat disks (due to the grain growth and dust settling in the outer disk).
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/59
- Title:
- Intrinsic AGN SEDs in PG quasars
- Short Name:
- J/MNRAS/471/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new analysis of the Palomar-Green quasar sample based on Spitzer and Herschel observations. (i) Assuming polycyclic aromatic hydrocarbon (PAH)-based star formation luminosities (L_SF_) similar to Symeonidis et al. (S16, 2016MNRAS.459..257S), we find mean and median intrinsic active galactic nucleus (AGN) spectral energy distributions (SEDs). These, in the far-infrared (FIR), appear hotter and significantly less luminous than the S16 mean intrinsic AGN SED. The differences are mostly due to our normalization of the individual SED that properly accounts for a small number of very FIR-luminous quasars. Our median, PAH-based SED represents ~6 per cent increase on the 1-243{mu}m luminosity of the extended Mor & Netzer (EM12, 2012MNRAS.420..526M) torus SED, while S16 find a significantly larger difference. It requires large-scale dust with T~20-30K, which, if optically thin and heated by the AGN, would be outside the host galaxy. (ii) We also explore the black hole and stellar mass growths, using L_SF_ estimates from fitting Herschel/PACS observations after subtracting the EM12 torus contribution. We use rough estimates of stellar mass, based on scaling relations, to divide our sample into groups: on, below and above the star formation main sequence (SFMS). Objects on the SFMS show a strong correlation between star formation luminosity and AGN bolometric luminosity, with a logarithmic slope of ~0.7. Finally, we derive the relative duty cycles of this and another sample of very luminous AGN at z=2-3.5. Large differences in this quantity indicate different evolutionary pathways for these two populations characterized by significantly different black hole masses.
- ID:
- ivo://CDS.VizieR/J/ApJ/841/76
- Title:
- Intrinsic far-IR SED of luminous AGNs
- Short Name:
- J/ApJ/841/76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The range of currently proposed active galactic nucleus (AGN) far-infrared templates results in uncertainties in retrieving host galaxy information from infrared observations and also undermines constraints on the outer part of the AGN torus. We discuss how to test and reconcile these templates. Physically, the fraction of the intrinsic AGN IR-processed luminosity compared with that from the central engine should be consistent with the dust-covering factor. In addition, besides reproducing the composite spectral energy distributions (SEDs) of quasars, a correct AGN IR template combined with an accurate library of star-forming galaxy templates should be able to reproduce the IR properties of the host galaxies, such as the luminosity-dependent SED shapes and aromatic feature strengths. We develop tests based on these expected behaviors and find that the shape of the AGN intrinsic far-IR emission drops off rapidly starting at ~20{mu}m and can be matched by an Elvis+ (1994, J/ApJS/95/1)-like template with a minor modification. Despite the variations in the near- to mid-IR bands, AGNs in quasars and Seyfert galaxies have remarkably similar intrinsic far-IR SEDs at {lambda}~20-100{mu}m, suggesting a similar emission character of the outermost region of the circumnuclear torus. The variations of the intrinsic AGN IR SEDs among the type-1 quasar population can be explained by the changing relative strengths of four major dust components with similar characteristic temperatures, and there is evidence for compact AGN-heated dusty structures at sub-kiloparsec scales in the far-IR.
