NOAO >   Observing Info >   Approved Programs >   2017A-0412

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Program Information for 2017A-0412


PI: Matt Berhsady, U. of Wisconsin, Madison, mab@astro.wisc.edu
Address: Astronomy Department, 475 N. Charter St, Madison, WI 53706 USA

CoI: Shravan Shetty, U. of Wisconsin, Madison
CoI: Chris Mihos, CWRU
CoI: Chris Mihos, CWRU
CoI: Paul Harding, CWRU

Title: Anomolous ionized gas clouds around nearby galaxies

Abstract: We propose to spectroscopically determine the origin of a faint, extended ($simarcmin$timesarcmin) cloud of diffuse ha emission recently discovered in deep narrow-band imaging of the interacting system M51. This cloud has no diffuse stellar counterpart, but shows some tentative continuity with known tidal streams of stars and gas in the M51 system. It may be gas stripped from M51a and shock heated during the collision, or an AGN-ionized circumgalactic cloud similar to ``Hanny's Voorwerp'' near IC 2497. Alternatively, it may have a more local origin, as part of the Milky Way's warm ionized medium or as an ultracompact high velocity cloud in the Milky Way's halo. A spectroscopic ha velocity measurement using SparsePak will cleanly verify its association either with M51 or the Milky Way, and the [NII] and [SII] lines in conjunction with ha will constrain the metallicity and help discriminate between shock-heating and photoionization scenarios for the cloud, in order to better probe the cloud's origin.

Program Type: WTAC

Scheduled Nights:
Run 1 (2017A):  WIYN/SPSPK -- 4n on Apr 24 - Apr 27 2017


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NOAO >   Observing Info >   Approved Programs >   2017A-0412

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