scholarly journals Hot & cold dust in M31: the resolved SED of Andromeda

2011 ◽  
Vol 7 (S284) ◽  
pp. 112-116
Author(s):  
Brent Groves ◽  
Oliver Krause ◽  
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Spectral Energy ◽  
Space Observatory ◽  
Photometric Observations ◽  
Total Luminosity ◽  
Andromeda Galaxy ◽  
Cold Dust ◽  
Insight Into

AbstractDue to its proximity, the Andromeda galaxy (M31, NGC 224) offers a unique insight into how the spectra of stars, dust, and gas combine to form the integrated Spectral Energy Distribution (SED) of galaxies. We introduce here Herschel Space Observatory PACS and SPIRE photometric observations of M31 which cover the far-infrared to sub-mm wavelengths (70-500 μm). These new observations reveal that the total IR luminosity of M31 is relatively weak, with LIR=109.65L⊙, only 10% of the total luminosity of M31. However, as seen in the previous studies of M31, the IR luminosity is dominated by a 10 kpc ring in all Herschel bands. This is distinct from the optical, where the bulge in the central 2kpc, dominates the luminosity, clearly demonstrating how different components at distinct positions in a galaxy contribute to make the integrated SED.

scholarly journals Far-infrared photometry of OJ 287 with the Herschel Space Observatory

2018 ◽  
Vol 610 ◽  
pp. A74
Author(s):  
Mark Kidger ◽  
Staszek Zola ◽  
Mauri Valtonen ◽  
Anne Lähteenmäki ◽  
Emilia Järvelä ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Light Curve ◽  
Spectral Index ◽  
Spectral Energy Distribution ◽  
Low Frequency ◽  
Far Infrared ◽  
Small Degree ◽  
Spectral Energy ◽  
Space Observatory ◽  
Near Ir

Context. The blazar OJ 287 has shown a ≈12 year quasi-periodicity over more than a century, in addition to the common properties of violent variability in all frequency ranges. It is the strongest known candidate to have a binary singularity in its central engine. Aim. We aim to better understand the different emission components by searching for correlated variability in the flux over four decades of frequency measurements. Methods. We combined data at frequencies from the millimetric to the visible to characterise the multifrequency light curve in April and May 2010. This includes the only photometric observations of OJ 287 made with the Herschel Space Observatory: five epochs of data obtained over 33 days at 250, 350, and 500 μm with Herschel-SPIRE. Results. Although we find that the variability at 37 GHz on timescales of a few weeks correlates with the visible to near-IR spectral energy distribution, there is a small degree of reddening in the continuum at lower flux levels that is revealed by the decreasing rate of decline in the light curve at lower frequencies. However, we see no clear evidence that a rapid flare detected in the light curve during our monitoring in the visible to near-IR light curve is seen either in the Herschel data or at 37 GHz, suggesting a low-frequency cut-off in the spectrum of such flares. Conclusions.We see only marginal evidence of variability in the observations with Herschel over a month, although this may be principally due to the poor sampling. The spectral energy distribution between 37 GHz and the visible can be characterised by two components of approximately constant spectral index: a visible to far-IR component of spectral index α = −0.95, and a far-IR to millimetric spectral index of α = −0.43. There is no evidence of an excess of emission that would be consistent with the 60 μmdust bump found in many active galactic nuclei.

scholarly journals Herschel Detects a Massive Dust Reservoir in Supernova 1987A

Science ◽  
2011 ◽  
Vol 333 (6047) ◽  
pp. 1258-1261 ◽  
Author(s):  
M. Matsuura ◽  
E. Dwek ◽  
M. Meixner ◽  
M. Otsuka ◽  
B. Babler ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Large Magellanic Cloud ◽  
Spectral Energy ◽  
The Sun ◽  
Supernova 1987A ◽  
Dust Mass ◽  
Cold Dust ◽  
Very High

We report far-infrared and submillimeter observations of supernova 1987A, the star whose explosion was observed on 23 February 1987 in the Large Magellanic Cloud, a galaxy located 160,000 light years away. The observations reveal the presence of a population of cold dust grains radiating with a temperature of about 17 to 23 kelvin at a rate of about 220 times the luminosity of the Sun. The intensity and spectral energy distribution of the emission suggest a dust mass of about 0.4 to 0.7 times the mass of the Sun. The radiation must originate from the supernova ejecta and requires the efficient precipitation of all refractory material into dust. Our observations imply that supernovae can produce the large dust masses detected in young galaxies at very high redshifts.

scholarly journals ISO Observations of Be Stars

2000 ◽  
Vol 175 ◽  
pp. 145-155
Author(s):  
L.B.F.M. Waters ◽  
N.R. Trams ◽  
S. Hony ◽  
A. de Koter ◽  
P.W. Morris ◽  
...  
Keyword(s):  
Infrared Spectrum ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Be Stars ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
Complex Behaviour ◽  
Infrared Spectral ◽  
Cold Dust ◽  
Disk Component

AbstractWe discuss the infrared spectral energy distribution of Be stars, focusing on new results obtained with the Infrared Space Observatory. The 60-160 μm flux of some Be stars is higher than expected, which may be due to cold dust or an outer disk component with enhanced densities. The infrared spectrum of Be stars is dominated by numerous HI recombination lines, whose line strengths show a complex behaviour. The electron temperature in the disk of ϒ Cas was found to be about 9500 K, and evidence for an elevated temperature near the upper part of the disk is presented. Be stars may be recognized from their infrared spectrum on the basis of HI line flux ratios.

scholarly journals HELP project - a dreamed-of multiwavelength dataset for SED fitting: The influence of used models for the main physical properties of galaxies

2019 ◽  
Vol 15 (S341) ◽  
pp. 39-43
Author(s):  
Katarzyna Małek ◽  
Veronique Buat ◽  
Denis Burgarella ◽  
Yannick Roehlly ◽  
Raphael Shirley ◽  
...  
Keyword(s):  
Physical Properties ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Spectral Energy ◽  
Infrared Photometry ◽  
Space Observatory ◽  
Distribution Fitting ◽  
Mass Estimation ◽  
Galaxy Sample ◽  
Peculiar Galaxies

AbstractThe Herschel Extragalactic Legacy Project (HELP) focuses to publish an astronomical multiwavelength catalogue of millions of objects over 1300 deg2 of the Herschel Space Observatory survey fields. Millions of galaxies with ultraviolet–far infrared photometry make HELP a perfect sample for testing spectral energy distribution fitting models, and to prepare tools for next-generation data. In the frame of HELP collaboration we estimated the main physical properties of all galaxies from the HELP database and we checked a new procedure to select peculiar galaxies from large galaxy sample and we investigated the influence of used modules for stellar mass estimation.

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