Karoline M. Gilbert

The ACS Nearby Galaxy Survey Treasury IV. The Star Formation History of NGC 2976 (2009)

Williams, Benjamin F., Dalcanton, Julianne J., Stilp, Adrienne, Gilbert, Karoline M., Roskar, Rok, Seth, Anil C., ...

We present resolved stellar photometry of NGC 2976 obtained with the Advanced Camera for Surveys (ACS) as part of the ACS Nearby Galaxy Survey Treasury (ANGST) program. The data cover the radial...

The SPLASH Survey: Internal Kinematics, Chemical Abundances, and Masses of the Andromeda I, II, III, VII, X, and XIV dSphs (2009)

Kalirai, Jason S., Beaton, Rachael L., Geha, Marla C., Gilbert, Karoline M., Guhathakurta, Puragra, Kirby, Evan N., ...

We present new Keck/DEIMOS spectroscopic observations of hundreds of individual stars along the sightline to Andromeda's first three discovered dwarf spheroidal galaxies (dSphs) - And I, II, and III,...

The Splash Survey: A Spectroscopic Portrait of Andromeda's Giant Southern Stream (2009)

Gilbert, Karoline M., Guhathakurta, Puragra, Kollipara, Priya, Beaton, Rachael L., Geha, Marla C., Kalirai, Jason S., ...

The giant southern stream (GSS) is the most prominent tidal debris feature in M31's stellar halo and covers a significant fraction of its southern quadrant. The GSS is a complex structure composed of...

The SPLASH Survey: A Spectroscopic Portrait of Andromeda's Giant Southern Stream (2009)

Gilbert, Karoline M., Guhathakurta, Puragra, Kollipara, Priya, Beaton, Rachael L., Geha, Marla C., Kalirai, Jason S., ...

The giant southern stream (GSS) is the most prominent tidal debris feature in M31's stellar halo. The GSS is composed of a relatively metal-rich, high surface-brightness "core" and a lower...

The SPLASH Survey: A Spectroscopic Analysis of the Metal-Poor, Low-Luminosity M31 dSph Satellite Andromeda X (2009)

Kalirai, Jason S., Zucker, Daniel B., Guhathakurta, Puragra, Geha, Marla, Kniazev, Alexei Y., Martinez-Delgado, David, ...

Andromeda X (And X) is a newly discovered low-luminosity M31 dwarf spheroidal galaxy (dSph) found by Zucker et al. (2007) in the Sloan Digital Sky Survey (SDSS - York et al. 2000). In this paper, we...

The Dominance of Metal-Rich Streams in Stellar Halos: A Comparison Between Substructure in M31 and Lambda-CDM Models (2009)

Gilbert, Karoline M., Font, Andreea S., Johnston, Kathryn V., Guhathakurta, Puragra

Extensive photometric and spectroscopic surveys of the Andromeda galaxy (M31) have discovered tidal debris features throughout M31's stellar halo. We present stellar kinematics and metallicities in...

The Role of Dwarf Galaxies in Building Large Stellar Halos (2009)

Kirby, Evan N., Guhathakurta, Puragra, Bullock, James S., Frebel, Anna, Geha, Marla, Gilbert, Karoline M., ...

The hierarchical theory of galaxy formation rests on the idea that smaller galactic structures merge to form the galaxies that we see today. The past decade has provided remarkable observational...

The Extended Star Formation History of the Andromeda Spheroid at 35 Kpc on the Minor Axis (2008)

Brown, Thomas M., Beaton, Rachael, Chiba, Masashi, Ferguson, Henry C., Gilbert, Karoline M., Guhathakurta, Puragra, ...

Using the HST ACS, we have obtained deep optical images reaching well below the oldest main sequence turnoff in fields on the southeast minor-axis of the Andromeda Galaxy, 35 kpc from the nucleus....

Was the Andromeda Stream Produced by a Disk Galaxy? (2008)

Fardal, Mark A., Babul, Arif, Guhathakurta, Puragra, Gilbert, Karoline M., Dodge, Cara

The halo region of M31 exhibits a startling level of stellar inhomogeneities, the most prominent of which is the "giant southern stream". Our previous analysis indicates that this stream, as well as...

Stellar Kinematics in the Complicated Inner Spheroid of M31: Discovery of Substructure Along the Southeastern Minor Axis and its Relationship to the Giant Southern Stream (2007)

Gilbert, Karoline M., Fardal, Mark, Kalirai, Jasonjot S., Guhathakurta, Puragra, Geha, Marla C., Isler, Jedidah, ...

We present the discovery of a kinematically-cold stellar population along the SE minor axis of the Andromeda galaxy (M31) that is likely the forward continuation of M31's giant southern stream. This...

Discovery of Andromeda XIV: A Dwarf Spheroidal Dynamical Rogue in the Local Group? (2007)

Majewski, Steven R., Beaton, Rachael L., Patterson, Richard J., Kalirai, Jasonjot S., Geha, Marla C., Muñoz, Ricardo R., ...

In the course of our survey of the outer halo of the Andromeda Galaxy we have discovered a remote, possible satellite of that system at a projected 162 kpc (11.7 degrees) radius. The fairly elongated...

The Extended Star Formation History of the Andromeda Spheroid at Twenty One Kiloparsecs on the Minor Axis (2007)

Brown, Thomas M., Smith, Ed, Ferguson, Henry C., Guhathakurta, Puragra, Kalirai, Jasonjot S., Rich, R. Michael, ...

Using the HST ACS, we have obtained deep optical images of a southeast minor-axis field in the Andromeda Galaxy, 21 kpc from the nucleus. In both star counts and metallicity, this field represents a...

A New Method for Isolating M31 Red Giant Stars: The Discovery of Stars out to a Radial Distance of 165 Kiloparsecs (2006)

Gilbert, Karoline M., Guhathakurta, Puragra, Kalirai, Jasonjot S., Rich, R. Michael, Majewski, Steven R., Ostheimer, James C., ...

We present a method for isolating a clean sample of red giant stars in the outerregions of the Andromeda spiral galaxy (M31) from an ongoing spectroscopic survey using the DEIMOS instrument on the...

Discovery of an Extended Halo of Metal-poor Stars in the Andromeda Spiral Galaxy (2006)

Guhathakurta, Puragra, Ostheimer, James C., Gilbert, Karoline M., Rich, R. Michael, Majewski, Steven R., Kalirai, Jasonjot S., ...

This paper has been withdrawn. Please see astro-ph/0502366.

Discovery of an extended halo of metal-poor stars in the Andromeda spiral galaxy (2005)

Guhathakurta, Puragra, Ostheimer, James C., Gilbert, Karoline M., Rich, R. Michael, Majewski, Steven R., Kalirai, Jasonjot S., ...

Understanding galaxy formation involves look-back and fossil-record studies of distant and nearby galaxies, respectively. Debris trails in our Galaxy's spheroidal halo of old stars provide evidence...

Dynamics and Stellar Content of the Giant Southern Stream in M31. I. Keck Spectroscopy of Red Giant Stars (2004)

Guhathakurta, Puragra, Rich, R. Michael, Reitzel, David B., Cooper, Michael C., Gilbert, Karoline M., Majewski, Steven R., ...

We present results from a large spectroscopic survey of M31 red giants using the Keck telescope/DEIMOS. Photometric pre-screening, based on the 100A-wide DDO51 band centered on the Mgb/MgH feature,...

An Intrinsic Baldwin Effect in the H-beta Broad Emission Line in the Spectrum of NGC 5548 (2002)

Gilbert, Karoline M., Peterson, Bradley M.

We investigate the possibility of an intrinsic Baldwin Effect (i.e.,nonlinear emission-line response to continuum variations) in the broad H-beta emission line of the active galaxy NGC 5548 using...

Near-IR and Optical Morphology of Spiral Galaxies (2002)

Eskridge, Paul B., Frogel, Jay A., Pogge, Richard W., Quillen, Alice C., Berlind, Andreas A., Davies, Roger L., ...

We announce the initial release of data from the Ohio State University Bright Spiral Galaxy Survey, a BVRJHK imaging survey of a well-defined sample of 205 bright, nearby spiral galaxies. We present...