A 500 Parsec Halo Surrounding the Galactic Globular NGC 1851 (2009)
Olszewski, Edward W., Saha, Abhijit, Knezek, Patricia, Subramaniam, Annapurni, De Boer, Thomas, Seitzer, Patrick
Using imaging that shows four magnitudes of main sequence stars, we have discovered that the Galactic globular cluster NGC 1851 is surrounded by a halo that is visible from the tidal radius of 700...
The Giant Branch of Omega Centauri. The Dependence of Kinematics on Abundance (2007)
John E. Norris, K. C. Freeman, Michel Mayor, Observatoire De Gen`eve, Patrick Seitzer
For a sample of some 400 red giants in the chemically inhomogeneous globular cluster ! Centauri we report correlations between the radial velocities of Mayor et al. (1997), which are accurate to !1...
A Search For Binaries In The Globular Cluster NGC 3201 (2007)
Patrick Côté, Douglas L. Welch, Philippe Fischer, Peter Tamblyn, ...
We present BV CCD and APM photometry, accurate astrometry and 1859 radial velocities for 1318 stars within ¸ 36 0 of the Galactic globular cluster NGC 3201. The field and cluster populations...
Saurabh Jha, Peter M. Garnavich, Robert P. Kirshner, Peter Challis, Alicia M. Soderberg, Lucas M. Macri, ...
We present optical and near-infrared photometry and spectroscopy of the Type Ia SN 1998bu in the Leo I Group galaxy M96 (NGC 3368). The data set consists of 356 photometric measurements and 29...
Schweizer, Francois, Seitzer, Patrick
This paper presents new images and spectroscopy of NGC 34 (Mrk 938) obtained with the du Pont 2.5-m and Baade 6.5-m telescopes at Las Campanas, plus photometry of an HST archival V image. This Mv =...
Elemental Abundance Ratios in Stars of the Outer Galactic Disk. II. Field Red Giants (2005)
Carney, Bruce W., Yong, David, De Almeida, Luisa, Seitzer, Patrick
We summarize a selection process to identify red giants in the direction of the southern warp of the Galactic disk, employing VI_C photometry and multi-object spectroscopy. We also present results...
The optical counterpart of an Ultra-luminous X-Ray Source in NGC 5204 (2005)
Ultra-luminous X-Ray sources are extra-nuclear point sources in external galaxies with $L_X=10^{39}$--$10^{41}$ erg/s and are among the most poorly understood X-ray sources. To help understand their...
Optical studies of ultra-luminous X-ray sources in nearby galaxies (2005)
Liu, Ji-Feng, Bregman, Joel N., Seitzer, Patrick, Irwin, Jimmy
Optical studies of ultra-luminous X-ray sources is an essential step in understanding the nature of these enigmatic sources, and in this paper we report our studies of five ULXs in NGC4559, NGC5194,...
A Two Hour Quasi-Period in an Ultra-luminous X-Ray source in NGC628 (2005)
Liu, Ji-Feng, Bregman, Joel N., Lloyd-Davies, Ed, Irwin, Jimmy, Espaillat, Catherine, Seitzer, Patrick
Quasi-periodic oscillations and X-ray spectroscopy are powerful probes of black hole masses and accretion disks, and here we apply these diagnostics to an ultraluminous X-ray source (ULX) in the...
Keck Spectroscopy of Two Young Globular Clusters in the Merger Remnant NGC 3921 (2004)
Schweizer, Francois, Seitzer, Patrick, Brodie, Jean P.
Low-resolution UV-to-visual spectra of two candidate globular clusters in the merger remnant NGC 3921 are presented. These two clusters of apparent magnitude V = 22.2 (Mv = -12.5) lie at projected...
An Ultra-luminous X-Ray Object with a 2 hour period in M51 (2002)
Liu, Ji-Feng, Bregman, Joel N., Irwin, Jimmy, Seitzer, Patrick
Ultra-luminous X-Ray Objects are off-nucleus point sources with $L_X=10^{39}$-$10^{41}$ erg/s but the nature of such systems are largely unidentified. Here we report a 2.1 hour period observed in a...
The optical counterpart of a Ultraluminous X-Ray Object in M81 (2002)
Liu, Ji-Feng, Bregman, Joel N., Seitzer, Patrick
Ultraluminous X-Ray Objects are off-nucleus point sources with $L_X=10^{39}$-$10^{41}$ erg/s and are among the most poorly understood X-ray sources. To help understand their nature, we are trying to...
Keck Spectroscopy of Globular Clusters in the Elliptical Galaxy NGC 3610 (2002)
Strader, Jay, Brodie, Jean P., Schweizer, Francois, Larsen, Soeren S., Seitzer, Patrick
We present moderate-resolution Keck spectra of nine candidate globular clusters in the possible merger-remnant elliptical galaxy NGC 3610. Eight of the objects appear to be bona fide globular...
A Scattered Light Echo around SN 1993J in M81 (2002)
Liu, Ji-Feng, Bregman, Joel N., Seitzer, Patrick
A light echo around SN 1993J was observed 8.2 years after explosion by a HST WFPC2 observation, adding to the small family of supernovae with light echoes. The light echo was formed by supernova...
Hubble Space Telescope Photometry of the Dwarf Spheroidal Galaxy ESO 410-G005 (2000)
Karachentsev, Igor D., Sharina, Margarita E., Grebel, Eva K., Dolphin, Andrew E., Geisler, Doug, Guhathakurta, Puragra, ...
We present HST WFPC2 imaging of the nearby low-surface-brightness dwarf spheroidal galaxy ESO 410-G005, which has been resolved into stars for the first time. The resulting color-magnitude diagram...
The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda II (1999)
Da Costa, G. S., Armandroff, T. E., Caldwell, Nelson, Seitzer, Patrick
The HST WFPC2 camera has been used to image Andromeda II, a dwarf spheroidal (dSph) companion to M31. The resulting color-magnitude diagrams reveal the morphology of the horizontal branch (HB) in...
Ages and Metallicities of Young Globular Clusters in the Merger Remnant NGC 7252 (1998)
Schweizer, Francois, Seitzer, Patrick
UV-to-visual spectra of eight young star clusters in the merger remnant and protoelliptical galaxy NGC 7252, obtained with the Blanco 4-m telescope on Cerro Tololo, are presented. These clusters lie...
Caldwell, Nelson, Armandroff, Taft E., Da Costa, G. S., Seitzer, Patrick
We have obtained HST WFPC2 images through the F555W and F814W filters of two M81 group dE's: BK5N and a new system, designated F8D1. The resulting color-magnitude diagrams show the upper two...
Optical Light Curves of the Type Ia Supernovae 1990N and 1991T (1997)
Lira, P., Suntzeff, Nicholas B., Phillips, M. M., Hamuy, Mario, Maza, Jose, Schommer, R. A., ...
We present UBVRI light curves for the bright Type Ia supernovae SN 1990N in NGC 4639 and SN 1991T in NGC 4527 based on photometry gathered in the course of the Calan/Tololo supernova program. Both...
The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda I (1996)
Da Costa, G. S., Armandroff, T. E., Caldwell, Nelson, Seitzer, Patrick
Images have been obtained with the Hubble Space Telescope WFPC2 camera of Andromeda I, a dwarf spheroidal (dSph) galaxy that lies in the outer halo of M31. The resulting color-magnitude diagrams...