scholarly journals Identifications of Faint IRAS Sources

1996 ◽  
Vol 171 ◽  
pp. 402-402
Author(s):  
M.W. Kümmel ◽  
S.J. Wagner
Keyword(s):  
Broad Band ◽  
Far Infrared ◽  
Power Laws ◽  
Point Sources ◽  
Spectral Energy ◽  
Energy Distributions ◽  
The North ◽  
Luminosity Functions ◽  
Error Circle ◽  
Radio Band

From overlapping scans in the IRAS all-sky survey and additional pointed observations the deepest far infrared survey before ISO exists in the region around the North Ecliptic Pole (NEP) (Hacking P. and Houck J.R., ApJS 63 p. 311). This survey contains detections up to 10 and fluxes up to 100 times fainter than the IRAS survey. In the central square degree around the NEP we combine the far IR-survey with deep radio data at 151 MHz and 1.5 GHz (Visser, A.E. et al., A&AS 110 p. 419, Kollgaard, R.I. et al., ApJS 93 p. 145) and own observation at 2.2μm (K′) and 435nm (B). The error circle around the IRAS source was chosen to include the true source with 85% probability (1.4 sigma). For 29 of the 32 IRAS sources we found at least one possible counterpart. Ten of the objects have multiple (up to four) counterparts in K′. Four of the IRAS sources have counterparts in the 1.5 GHz survey. The higher accuracy of the radio position (∼ 1″) allowed an unambiguous identification of the K′ counterpart. None of the IRAS sources could be found in the 151 MHz survey. The broad band spectra of the three galaxies with measured radio flux exhibit maximum emission between the radio band and 100μm which corresponds to emission by cool dust (< 50 K). Contrary to the infrared luminosity functions at 12μm and 60μm which show power laws, the K′ luminosity function is bimodal. The brightest K′ objects are all point sources. Due to the small number statistics the power law indices of the luminosity functions can not be distinguished. We find a linear relationship between the K′ flux and the flux at 60μm and 12μm over at least one decade. The large deviations by individual sources make an identification of the correct counterpart through this relation impossible. The spectral energy distributions of unambiguously identified sources span only one decade in energy (vSv), i.e. they have flat energy distributions. This suggests an identification of K′ objects with flat energy distribution in case of multiple counterparts.

scholarly journals From rest-frame luminosity functions to observer-frame colour distributions: tackling the next challenge in cosmological simulations

2020 ◽  
Vol 497 (3) ◽  
pp. 3026-3046 ◽  
Author(s):  
Matías Bravo ◽  
Claudia del P Lagos ◽  
Aaron S G Robotham ◽  
Sabine Bellstedt ◽  
Danail Obreschkow
Keyword(s):  
Survey Design ◽  
Target Selection ◽  
Broad Band ◽  
Complex Mixture ◽  
Far Infrared ◽  
Bimodal Distribution ◽  
Spectral Energy ◽  
Recent Success ◽  
Luminosity Functions ◽  
Radiation Output

ABSTRACT Galaxy spectral energy distributions (SEDs) remain among the most challenging yet informative quantities to reproduce in simulations due to the large and complex mixture of physical processes that shape the radiation output of a galaxy. With the increasing number of surveys utilizing broad-band colours as part of their target selection criteria, the production of realistic SEDs in simulations is necessary for assisting in survey design and interpretation of observations. The recent success in reproducing the observed luminosity functions (LFs) from far-ultraviolet (UV) to far-infrared (IR), using the state-of-the-art semi-analytic model shark and the SED generator ProSpect, represents a critical step towards better galaxy colour predictions. We show that with shark and ProSpect we can closely reproduce the optical colour distributions observed in the panchromatic Galaxy And Mass Assembly (GAMA) survey. The treatment of feedback, star formation, central–satellite interactions, and radiation reprocessing by dust are critical for this achievement. The first three processes create a bimodal distribution, while dust attenuation defines the location and shape of the blue and red populations. While a naive comparison between observation and simulations displays the known issue of overquenching of satellite galaxies, the introduction of empirically motivated observational errors and classification from the same group finder used in GAMA greatly reduces this tension. The introduction of random reassignment of ${\sim} 15{{\ \rm per\ cent}}$ of centrals/satellites as satellites/centrals on the simulation classification closely resembles the outcome of the group finder, providing a computationally less intensive method to compare simulations with observations.

scholarly journals The Nature of the Emission-line Nebulae in Powerful Far-infrared Galaxies

1990 ◽  
Vol 124 ◽  
pp. 409-413
Author(s):  
Lee Armus ◽  
Timothy M. Heckman ◽  
George K. Miley
Keyword(s):  
Emission Line ◽  
Narrow Band ◽  
Broad Band ◽  
Far Infrared ◽  
Interacting Galaxies ◽  
Spectral Energy ◽  
Infrared Galaxies ◽  
Energy Distributions ◽  
Infrared Spectral ◽  
The Mean

AbstractWe discuss our program of narrow-band (Hα + [Nil]) imaging of a sample of 30 powerful far-infrared galaxies (FIRG’s) chosen to have far-infrared spectral energy distributions similar to the prototype FIRG’s Arp 220, NGC 3690, NGC 6240, and M82. The emission-line nebulae of these IR color-selected sample (ICSS) galaxies as a class are both impressively large (mean half light radius, r ~1.3 Kpc, and mean diameter, D ~16 Kpc) and luminous (LTOT ~108 Lo; uncorrected for internal extinction). The mean total Hα + [Nil] luminosity of the FIRG’s is comparable to that found for pairs of optically selected interacting galaxies (Bushouse, Lamb, and Werner 1988), but is a factor of ~5 greater than that of isolated spirals (Kennicutt and Kent 1983). Only ~25% of the nearby (z ≤ 0.10) FIRG’s have morphologies suggesting that large HII~regions contribuí significantly to their emission-line appearance. The broad-band morphologies of our IR color-selected galaxies fall into three major categories. Nearly 75% are single galaxy systems, with the remaining FIRG’s being either multiple nuclei systems, or members of interacting pairs. Since we see few (10%) currently interacting FIRG’s, yet many (80%) with highly distorted continuum morphologies, our IR color criteria may be preferentially selecting galaxies that have undergone highly inelastic, rapidly merging interactions.

scholarly journals The spectral energy distributions of active galactic nuclei

2019 ◽  
Vol 489 (3) ◽  
pp. 3351-3367 ◽  
Author(s):  
M J I Brown ◽  
K J Duncan ◽  
H Landt ◽  
M Kirk ◽  
C Ricci ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Flux Density ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Power Laws ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Photometric Redshifts ◽  
X Ray

ABSTRACT We present spectral energy distributions (SEDs) of 41 active galactic nuclei, derived from multiwavelength photometry and archival spectroscopy. All of the SEDs span at least 0.09 to 30 $\mu$m, but in some instances wavelength coverage extends into the X-ray, far-infrared, and radio. For some active galactic nuclei (AGNs) we have fitted the measured far-infrared photometry with greybody models, while radio flux density measurements have been approximated by power laws or polynomials. We have been able to fill some of the gaps in the spectral coverage using interpolation or extrapolation of simple models. In addition to the 41 individual AGN SEDs, we have produced 72 Seyfert SEDs by mixing SEDs of the central regions of Seyferts with galaxy SEDs. Relative to the literature, our templates have broader wavelength coverage and/or higher spectral resolution. We have tested the utility of our SEDs by using them to generate photometric redshifts for 0 &lt; z ≤ 6.12 AGNs in the Boötes field (selected with X-ray, IR, and optical criteria) and, relative to SEDs from the literature, they produce comparable or better photometric redshifts with reduced flux density residuals.

The K-Band Luminosity Function

1996 ◽  
Vol 171 ◽  
pp. 465-465
Author(s):  
S.J. Wagner ◽  
M.W. Kümmel
Keyword(s):  
Luminosity Function ◽  
Broad Band ◽  
Point Sources ◽  
Spatial Sampling ◽  
Energy Distributions ◽  
Band Energy ◽  
Sky Surveys ◽  
X Ray ◽  
The North ◽  
K Band

Investigations of broad band energy distributions of specific classes of sources requires homogeneous samples of a sufficiently large number of objects. Deep and homogeneous surveys in those energy ranges which are accessible to satellites only are rare. One such a field in the north ecliptic pole (NEP). The ROSAT and IRAS whole sky surveys and deep additional observations by other satellites make the NEP the region of the deepest mid-IR and X-ray observations. We performed complete surveys in three optical/IR colors at 460nm, 700nm, and 2.1 μm (B, R, and K′) within a one square degree field around the NEP. Limiting magnitudes in the three bands are 23, 24, and 19, respectively. The optical bands are observed with sufficient spatial sampling to classify extended and point sources. Down to levels which still correspond to high completeness limits we detect 80.000, 240.000 and 25.000 sources in B, R, and K′, respectively.

scholarly journals Accretion and Outflow Activity in the Earliest Phases of Star-Formation: CO, Sub-mm Continuum, and Near-Infrared Observations

1997 ◽  
Vol 163 ◽  
pp. 725-726
Author(s):  
K.-W. Hodapp ◽  
E. F. Ladd
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Point Sources ◽  
Spectral Energy ◽  
Infrared Observations ◽  
Circumstellar Material ◽  
Dense Cores ◽  
Wavelength Radiation ◽  
Main Component

Stars in the earliest phases of their formation, i.e., those accreting the main component of their final mass, are deeply embedded within dense cores of dust and molecular material. Because of the high line-of-sight extinction and the large amount of circumstellar material, stellar emission is reprocessed by dust into long wavelength radiation, typically in the far-infrared and sub-millimeter bands. Consequently, the youngest sources are strong submillimeter continuum sources, and often undetectable as point sources in the near-infrared and optical. The most deeply embedded of these sources have been labelled “Class 0” sources by André, Ward-Thompson, & Barsony (1994), in an extension of the spectral energy distribution classification scheme first proposed by Adams, Lada, & Shu (1987).

scholarly journals The Far‐Infrared Spectral Energy Distributions of X‐Ray–selected Active Galaxies

2003 ◽  
Vol 590 (1) ◽  
pp. 128-148 ◽  
Author(s):  
Joanna K. Kuraszkiewicz ◽  
Belinda J. Wilkes ◽  
Eric ◽  
J. Hooper ◽  
Kim K. McLeod ◽  
...  
Keyword(s):  
Far Infrared ◽  
Active Galaxies ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
X Ray ◽  
Infrared Spectral

scholarly journals The Far-Infrared emission of the first (z ∼ 6) massive galaxies

2019 ◽  
Vol 15 (S352) ◽  
pp. 246-247
Author(s):  
George H. Rieke ◽  
Maria Emilia De Rossi ◽  
Irene Shivaei ◽  
Volker Bromm ◽  
Jianwei Lyu
Keyword(s):  
Interstellar Dust ◽  
Far Infrared ◽  
High Energy ◽  
Infrared Emission ◽  
High Energy Density ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Massive Galaxies ◽  
Very High Energy ◽  
Lower Redshift

AbstractThe first massive galaxies (z ∼ 6) have (1) very high energy density due to their small diameters and extreme luminosities in young stars and (2) interstellar dust relatively deficient in carbon compared with silicates. Both of these attributes should raise their interstellar dust temperatures compared with lower redshift galaxies. Not only is this temperature trend observed, but the high-z spectral energy distributions (SEDs) are very broad due to very warm dust. As a result total infrared luminosities – and star formation rates – at the highest redshifts estimated by fitting blackbodies to submm- and mm-wave observations can be low by a factor of ∼2.

scholarly journals WELL-SAMPLED FAR-INFRARED SPECTRAL ENERGY DISTRIBUTIONS OFz∼ 2 GALAXIES: EVIDENCE FOR SCALED UP COOL GALAXIES

2010 ◽  
Vol 725 (1) ◽  
pp. 742-749 ◽  
Author(s):  
Adam Muzzin ◽  
Pieter van Dokkum ◽  
Mariska Kriek ◽  
Ivo Labbé ◽  
Iara Cury ◽  
...  
Keyword(s):  
Far Infrared ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Infrared Spectral

scholarly journals The spectral energy distributions of the entire Herschel Reference Survey

2011 ◽  
Vol 7 (S284) ◽  
pp. 283-285
Author(s):  
Laure Ciesla ◽  
Keyword(s):  
Far Infrared ◽  
Infrared Emission ◽  
Spectral Energy ◽  
Physical Parameters ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Distant Galaxies ◽  
First Results ◽  
Nearby Galaxies ◽  
Stellar Masses

AbstractWe present the spectral energy distributions (SED) of the 323 galaxies of the Herschel Reference Survey. In order to provide templates for nearby galaxies calibrated on physical parameters, we computed mean SEDs per bin of morphological types and stellar masses. They will be very useful to study more distant galaxies and their evolution with redshift. This preliminary work aims to study how the most commonly used libraries (Chary & Elbaz 2001, Dale & Helou 2002 and Draine & Li 2007) reproduce the far-infrared emission of galaxies. First results show that they reproduce well the far-infrared part of mean SEDs. For single galaxies the Draine & Li (2007) models seem to reproduce very well the far-infrared emission, as does the Dale & Helou (2002).

scholarly journals Using the CIFIST grid of CO5BOLD 3D model atmospheres to study the effects of stellar granulation on photometric colours

2018 ◽  
Vol 613 ◽  
pp. A24 ◽  
Author(s):  
A. Kučinskas ◽  
J. Klevas ◽  
H.-G. Ludwig ◽  
P. Bonifacio ◽  
M. Steffen ◽  
...  
Keyword(s):  
Main Sequence ◽  
Broad Band ◽  
Stellar Atmospheres ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Different Types ◽  
Convective Motions ◽  
Effective Temperatures ◽  
Red Giant ◽  
Colour Indices

Aims. We studied the influence of convection on the spectral energy distributions (SEDs), photometric magnitudes, and colour indices of different types of stars across the H–R diagram. Methods. The 3D hydrodynamical CO5BOLD, averaged ⟨3D⟩, and 1D hydrostatic LHD model atmospheres were used to compute SEDs of stars on the main sequence (MS), main sequence turn-off (TO), subgiant branch (SGB), and red giant branch (RGB), in each case at two different effective temperatures and two metallicities, [M∕H] = 0.0 and − 2.0. Using the obtained SEDs, we calculated photometric magnitudes and colour indices in the broad-band Johnson-Cousins UBVRI and 2MASS JHKs, and the medium-band Strömgren uvby photometric systems. Results. The 3D–1D differences in photometric magnitudes and colour indices are small in both photometric systems and typically do not exceed ± 0.03 mag. Only in the case of the coolest giants located on the upper RGB are the differences in the U and u bands able reach ≈−0.2 mag at [M∕H] = 0.0 and ≈−0.1 mag at [M∕H] = −2.0. Generally, the 3D–1D differences are largest in the blue-UV part of the spectrum and decrease towards longer wavelengths. They are also sensitive to the effective temperature and are significantly smaller in hotter stars. Metallicity also plays a role and leads to slightly larger 3D–1D differences at [M∕H] = 0.0. All these patterns are caused by a complex interplay between the radiation field, opacities, and horizontal temperature fluctuations that occur due to convective motions in stellar atmospheres. Although small, the 3D–1D differences in the magnitudes and colour indices are nevertheless comparable to or larger than typical photometric uncertainties and may therefore cause non-negligible systematic differences in the estimated effective temperatures.

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