NOAO >   Observing Info >   Approved Programs >   2012B-0540

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Program Information for 2012B-0540


PI: Puragra Guhathakurta, UC Santa Cruz, raja@ucolick.org
Address: Astronomy Department, 1156 High Street, Santa Cruz, CA 95064 USA

CoI: Rachael L Beaton, U. of Virginia
CoI: Karoline M Gilbert, U. of Washington
CoI: Martha Boyer, STScI
CoI: Kathryn V Johnston, Columbia U.
CoI: Rob Swaters, NOAO
CoI: Elisa Toloba, UC Santa Cruz
CoI: Masashi Chiba, Tohoku University
CoI: Arjun Dey, NOAO
CoI: Jason Kalirai, STScI
CoI: Evan N. Kirby, California Institute of Technology
CoI: Steven R Majewski, U. of Virginia
CoI: Knut Olsen, NOAO
CoI: Richard Patterson, U. of Virginia
CoI: Mikito Tanaka, Tohoku University
CoI: Katherine Hamren, UC Santa Cruz
CoI: Claire Dorman, UC Santa Cruz

Title: NEWFIRM Survey of Intermediate Age Populations in M31's Halo: A Test of (Lambda)CDM

Abstract: Owing to their long dynamical times, galaxy stellar halos provide unique insight into their formation history. Recent detailed hydrodynamical and $N$-body simulations, carried out within the framework of a $\Lambda$CDM cosmogony, can track the formation of single Milky Way sized galaxies. It is clear from these simulations that halo stars can have three distinct origins: accretion of satellites, {\it in situ\/} formation, and kicked up disk. Studies of these populations in the Milky Way are complicated by our internal perspective, but the Andromda galaxy (M31) offers the ideal combination of an external global perspective and detail. Our SPLASH team used KPNO/4-m+MOSAIC optical ($M$, $T_2$, $DDO51$) imaging of 72~fields and Keck/DEIMOS spectroscopy of a few $\times$ 10$^4$ RGB stars across this area to discover the true metal-poor halo of M31 and has measured key properties out to 2/3 of the virial radius ($R\sim200$~kpc): surface brightness profile, substructure, kinematics, [Fe/H], and [$\alpha$/Fe]. By adding to this our proposed KPNO/4-m+NEWFIRM wide-field near-infrared ($J$, $K_s$) imaging survey of intermediate-age AGB stars, we will obtain the critical missing piece for testing halo formation models: a constraint on the stellar age distribution in M31's halo.

Program Type: Survey

Scheduled Nights:
Run 1 (2012B):  KP-4m/NEWFIRM -- 13n on Nov 02 - Nov 06 2012, Nov 21 - Nov 28 2012
Run 1 (2013B):  KP-4m/NEWFIRM -- 14n on Oct 16 - Oct 23 2013, Nov 08 - Nov 13 2013
Run 1 (2014B):  KP-4m/NEWFIRM -- 7n on Oct 03 - Oct 09 2014


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2012B-0540

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