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Extragalactic abstracts - IRSA - California Institute of Technology

Extragalactic abstracts - IRSA - California Institute of Technology

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Spitzer_Approved_<strong>Extragalactic</strong><br />

Mar 25, 10 16:24 Page 5/742<br />

Spitzer Space Telescope − General Observer Proposal #3680<br />

Ejecta and Interstellar Dust in Magellanic Clouds Supernova Remnants<br />

Principal Investigator: Kazimierz Borkowski<br />

Institution: North Carolina State University<br />

Technical Contact: Kazimierz Borkowski, North Carolina State University<br />

Co−Investigators:<br />

William Blair, Johns Hopkins University<br />

Parviz Ghavamian, Johns Hopkins University<br />

Sean Hendrick, North Carolina State University<br />

Knox Long, Space Science Telescope <strong>Institute</strong><br />

John Raymond, Harvard University<br />

Stephen Reynolds, North Carolina State University<br />

Ravi Sankrit, Johns Hopkins University<br />

Chris Smith, National Optical Astronomy Observatory<br />

Frank Winkler, Middlebury College<br />

Science Category: local group galaxies<br />

Observing Modes: IracMap MipsPhot<br />

Hours Approved: 21.4<br />

Abstract:<br />

Stellar explosions govern the interstellar dust lifecycle. In the early<br />

Universe, supernovae (SN) injected the first heavy elements into the<br />

interstellar medium (ISM). A significant fraction <strong>of</strong> ejecta was dust. Dust is<br />

destroyed today in supernova remnant’s (SNR) blast waves. Our current<br />

understanding <strong>of</strong> both formation <strong>of</strong> dust in SNe and destruction <strong>of</strong> dust in blast<br />

waves is poorly understood. We propose to observe a complete sample <strong>of</strong> SNRs in<br />

Magellanic Clouds (MCs) with the Spitzer Space Telescope (SST) in order to<br />

dramatically advance our knowledge <strong>of</strong> these processes. Heavy−element ejecta have<br />

been detected in more than one third <strong>of</strong> all SNRs in MCs, mostly in X−rays. Dust<br />

within these ejecta is collisionally heated by electrons and ions, and<br />

reradiates the absorbed energy in the far−IR. We propose deep MIPS and IRAC<br />

imaging <strong>of</strong> all MC SNRs with heavy−element ejecta in order to detect and study<br />

ejecta dust. We will determine dust temperature, dust mass, and its spatial<br />

distribution within ejecta. We will also detect dust in the ISM swept by SNR<br />

blast waves. This dust is destroyed by sputtering in hot X−ray emitting plasmas.<br />

We will learn about dust destruction by measuring the dust/gas mass ratio behind<br />

blast waves through a combined IR−X−ray analysis. Sputtering preferentially<br />

destroys small dust grains, modifying the grain size distribution. This strongly<br />

affects thermal dust emission in the IRAC bands which is produced by small<br />

grains. We will learn about the destruction <strong>of</strong> small grains by observing spatial<br />

variations <strong>of</strong> IRAC band ratios behind blast waves. An unbiased survey <strong>of</strong> all<br />

SNRs in MCs is necessary for understanding <strong>of</strong> dust destruction. We propose 24<br />

micron MIPS imaging <strong>of</strong> all MC SNRs, and 70 micron MIPS imaging <strong>of</strong> X−ray bright<br />

SNRs. The proposed MIPS and IRAC imaging <strong>of</strong> MC SNRs will provide us with unique<br />

information about ejecta dust in a large sample <strong>of</strong> SNRs and about destruction <strong>of</strong><br />

the ISM dust.<br />

Spitzer_Approved_<strong>Extragalactic</strong><br />

Printed_by_SSC<br />

Mar 25, 10 16:24 Page 6/742<br />

Spitzer Space Telescope − Archive Research Proposal #40568<br />

Star Clusters in M31: Stellar Populations and Mass Loss<br />

Principal Investigator: Jean Brodie<br />

Institution: University <strong>of</strong> <strong>California</strong>, Santa Cruz<br />

Technical Contact: Jean Brodie, University <strong>of</strong> <strong>California</strong>, Santa Cruz<br />

Co−Investigators:<br />

Jay Strader, University <strong>of</strong> <strong>California</strong>, Santa Cruz<br />

Jacco van Loon, Keele University<br />

Science Category: local group galaxies<br />

Dollars Approved: 48294.0<br />

Abstract:<br />

We propose an imaging study <strong>of</strong> massive star clusters in M31 using archival<br />

Spitzer imaging with IRAC and MIPS. We have two distinct goals: (1) Estimate<br />

cluster ages, metallicities, and reddenings through panchromatic FUV to mid−IR<br />

imaging, and (2) Assess the production rate and lifetime <strong>of</strong> dust in the<br />

intracluster medium (ICM) as a function <strong>of</strong> cluster properties. Our results will<br />

give important constraints on the star formation history <strong>of</strong> M31 and on mass loss<br />

in stellar clusters.<br />

Thursday March 25, 2010 xgal_covers.txt<br />

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