Search Publications
Blue Straggler Star Populations in Globular Clusters. I. Dynamical Properties of Blue Straggler Stars in NGC 3201, NGC 6218, and ω Centauri
Puzia, Thomas H.; Simunovic, Mirko
We present the first dynamical study of blue straggler stars (BSSs) in three Galactic globular clusters, NGC 3201, NGC 5139 (ω Cen), and NGC 6218, based on medium-resolution spectroscopy (R ≈ 10, 000) obtained with the Inamori-Magellan Areal Camera & Spectrograph mounted at the 6.5 m Baade Magellan telescope. Our BSS candidate selection techni…
Herschel Observations of Dust around the High-mass X-Ray Binary GX 301-2
Chaty, S.; Rahoui, F.; Servillat, M. +2 more
We aim at characterizing the structure of the gas and dust around the high-mass X-ray binary GX 301-2, a highly obscured X-ray binary hosting a hypergiant (HG) star and a neutron star, in order to better constrain its evolution. We used Herschel PACS to observe GX 301-2 in the far infrared and completed the spectral energy distribution of the sour…
The Shock-induced Star Formation Sequence Resulting from a Constant Spiral Pattern Speed
Martínez-García, Eric E.; Puerari, Ivânio
We utilize a suite of multiwavelength data of nine nearby spirals to analyze the shock-induced star formation sequence that may result from a constant spiral pattern speed. The sequence involves tracers as the H I, CO 24 µm, and FUV, where the spiral arms were analyzed with Fourier techniques in order to obtain their azimuthal phases as a fu…
The CoRoT Discovery of a Unique Triple-mode Cepheid in the Galaxy
Poretti, E.; Baglin, A.; Weiss, W. W.
The exploitation of the CoRoT treasure of stars observed in the exoplanetary field allowed the detection of a unusual triple-mode Cepheid in the Milky Way, CoRoT 0223989566. The two modes with the largest amplitudes and a period ratio of 0.80 are identified with the first (P 1 = 1.29 days) and second (P 2 = 1.03 days) radial …
The Jet and Arc Molecular Clouds toward Westerlund 2, RCW 49, and HESS J1023-575 12CO and 13CO (J = 2-1 and J = 1-0) observations with NANTEN2 and Mopra Telescope
Aharonian, F.; Fukui, Y.; Onishi, T. +20 more
We have made new CO observations of two molecular clouds, which we call "jet" and "arc" clouds, toward the stellar cluster Westerlund 2 and the TeV γ-ray source HESS J1023-575. The jet cloud shows a linear structure from the position of Westerlund 2 on the east. In addition, we have found a new counter jet cloud on the west. The arc cloud shows a …
The RR Lyrae Variable Population in the Phoenix Dwarf Galaxy
Sarajedini, Ata; Yang, Soung-Chul; Ordoñez, Antonio J.
We present the first detailed study of the RR Lyrae variable population in the Local Group dSph/dIrr transition galaxy, Phoenix, using previously obtained HST/WFPC2 observations of the galaxy. We utilize template light curve fitting routines to obtain best fit light curves for RR Lyrae variables in Phoenix. Our technique has identified 78 highly p…
GHOSTS I: A New Faint Very Isolated Dwarf Galaxy at D = 12 ± 2 Mpc
Bell, Eric F.; Holwerda, Benne W.; Monachesi, Antonela +8 more
We report the discovery of a new faint dwarf galaxy, GHOSTS I, using HST/ACS data from one of our GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disk, and Star clusters) fields. Its detected individual stars populate an approximately 1 mag range of its luminosity function (LF). Using synthetic color-magnitude diagrams (CMDs) to compare wit…
Unresolved Mixed Polarity Magnetic Fields at Flux Cancellation Site in Solar Photosphere at 0.''3 Spatial Resolution
Lites, Bruce W.; Kubo, Masahito; Chye Low, Boon
This is a follow-up investigation of a magnetic flux cancellation event at a polarity inversion line (PIL) on the Sun observed with the spectropolarimeter on board Hinode. Anomalous circular polarization (Stokes V) profiles are observed in the photosphere along the PIL at the cancellation sites. Kubo et al. previously reported that the theoretical…
The Black Hole Mass and the Stellar Ring in NGC 3706
Gebhardt, Karl; Kormendy, John; Lauer, Tod R. +4 more
We determine the mass of the nuclear black hole (M) in NGC 3706, an early-type galaxy with a central surface brightness minimum arising from an apparent stellar ring, which is misaligned with respect to the galaxy's major axis at larger radii. We fit new HST/STIS and archival data with axisymmetric orbit models to determine M, mass-to-light ratio …
Modeling X-Ray Emission around Galaxies
Bregman, Joel N.; Anderson, Michael E.
Extended X-ray emission can be studied by spatial surface brightness measurements or by spectral analysis, but the two methods can disagree at low intensity levels. Here we present an improved method for spatial analysis that can be extended to include spectral information simultaneously. We construct a model for the entire image in a given energy…