maarten baes attenuation of starlight in virgo cluster galaxies hevics consortium meeting, garching...
TRANSCRIPT
![Page 1: Maarten Baes Attenuation of starlight in Virgo Cluster galaxies HeViCS consortium meeting, Garching bei München, 8-9 April 2013](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697c00b1a28abf838cc7fa6/html5/thumbnails/1.jpg)
Maarten Baes
Attenuation of starlight in Virgo Cluster galaxies
HeViCS consortium meeting, Garching bei München, 8-9 April 2013
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Dust extinction
We want to know how much radiation is attenuated by interstellar dust in galaxies at every wavelength
• Important for correcting observed fluxes and converting them to intrinsic luminosities
• Dust extinction is the key to understanding the heating sources of the dust question (important e.g. for the use of FIR emission as a tool to estimate the SFR)
• Shape of the extinction curve can tell us something on the composition and size distribution of dust grains in different environments.
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Fraction of Ldust to Ltot
Major result based on IRAS bright galaxies: Ldust is about 30% of Ltot
Study of 28 late-type galaxies with ISOPHOT by Popescu & Tuffs (2002): same result (but with a spread in Hubble type)
Two effects that work in opposite sense:• IRAS bright galaxies were selected
as FIR luminous sources: you would expect a higher value of Ldust/Ltot
• Virgo sample uses ISOPHOT data out to 200 µm: traces also the cool dust luminosity not traced by IRAS
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HeViCS study of attenuation
We can do much better now thanks to HeViCS
• Sample: we can create larger and better sampleso FIR/submm selected sample (based on BGS or Planck)o optically selected sample (VCC)
• Much more reliable data to determine both Ltot and Ldust: panchromatic combination of GALEX, SDSS, UKIDSS/2MASS, WISE, (Spitzer), Herschel
• Interesting option: MagPhys (self-consistent modelling of the UV/optical/NIR and MIR/FIR/submm emission using energy balance arguments)
• We can do more than just calculate Ldust/Ltot: determine at which wavelengths dust absorbs most energy (UV or optical ?)
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MagPhys example
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Action plan
Step 1: determine suitable samples (optically selected and FIR/submm selected)
Step 2: collect panchromatic data sets• PACS/SPIRE: in hand• SDSS/GALEX: from Luca’s HRS paper (+ add missing)• 2MASS/UKIDSS: from archive ?• WISE: from archive ?
Step 3: MagPhys modelling – Sébastien/Ilse are experienced users…
Step 4: analysis and interpretation
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Maarten Baes
Attenuation of starlight in Virgo Cluster galaxies
HeViCS consortium meeting, Garching bei München, 8-9 April 2013