Search Publications
Multiwavelength Observations of 3C 454.3. II. The AGILE 2007 December Campaign
Antonelli, L. A.; Costa, E.; Mereghetti, S. +76 more
We report on the second Astrorivelatore Gamma a Immagini Leggero (AGILE) multiwavelength campaign of the blazar 3C 454.3 during the first half of 2007 December. This campaign involved AGILE, Spitzer, Swift, Suzaku, the Whole Earth Blazar Telescope (WEBT) consortium, the Rapid Eye Mount (REM), and the Multicolor Imaging Telescopes for Survey and Mo…
Fermi Large Area Telescope Detection of Pulsed γ-rays from the Vela-like Pulsars PSR J1048-5832 and PSR J2229+6114
Ozaki, M.; Caraveo, P. A.; Halpern, J. +173 more
We report the detection of γ-ray pulsations (>=0.1 GeV) from PSR J2229+6114 and PSR J1048-5832, the latter having been detected as a low-significance pulsar by EGRET. Data in the γ-ray band were acquired by the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope, while the radio rotational ephemerides used to fold the γ-ray li…
Pulsed Gamma Rays from the Millisecond Pulsar J0030+0451 with the Fermi Large Area Telescope
Caraveo, P. A.; Frailis, M.; Orlando, E. +169 more
We report the discovery of gamma-ray pulsations from the nearby isolated millisecond pulsar (MSP) PSR J0030+0451 with the Large Area Telescope on the Fermi Gamma-ray Space Telescope (formerly GLAST). This discovery makes PSR J0030+0451 the second MSP to be detected in gamma rays after PSR J0218+4232, observed by the EGRET instrument on the Compton…
Helium-core White Dwarfs in the Globular Cluster NGC 6397
Anderson, Jay; Cool, Adrienne M.; Serenelli, Aldo M. +3 more
We present results of a study of the central regions of NGC 6397 using Hubble Space Telescope's Advanced Camera for Surveys (HST ACS), focusing on a group of 24 faint blue stars that form a sequence parallel to, but brighter than, the more populated sequence of carbon-oxygen white dwarfs (CO WDs). Using F625W, F435W, and F658N filters with the Wid…
Observational Evidence on the Presence of an Outer Reflecting Boundary in Solar Energetic Particle Events
Wang, Linghua; Reames, Donald V.; Tan, Lun C. +2 more
We have focused primarily on the 2001 September 24 solar energetic particle (SEP) event to verify previous indications of the presence of an outer reflecting boundary of SEPs. By using energetic electron and ion data obtained from multi-spacecraft observations, we have identified a collimated particle beam consisting of reflected particles returni…
Observational Constraints on the Co-Evolution of Supermassive Black Holes and Galaxies
Jahnke, K.; Meisenheimer, K.; Rix, H. -W. +6 more
The star formation rate (SFR) and black hole accretion rate (BHAR) functions are measured to be proportional to each other at z lsim 3. This close correspondence between SF and BHA would naturally yield a BH mass-galaxy mass correlation, whereas a BH mass-bulge mass correlation is observed. To explore this apparent contradiction, we study the SF i…
Constraining the Spin-Down of the Nearby Isolated Neutron Star RX J2143.0+0654
van Kerkwijk, M. H.; Kaplan, D. L.
Magnetic field estimates for nearby isolated neutron stars (INS) help to constrain both the characteristics of the population and the nature of their peculiar X-ray spectra. From a series of XMM -Newton observations of RX J2143.0+0654, we measure a spin-down rate of \dot{ν}= {(-4.6± 2.0) × 10^{-16}} Hz s^{-1}. While this does not allow a definitiv…
The Mean Type Ia Supernova Spectrum Over the Past Nine Gigayears
Gal-Yam, A.; Sullivan, M.; Nugent, P. E. +3 more
We examine the possibility of evolution with redshift in the mean rest-frame ultraviolet (UV; λ lsim 4500 Å) spectrum of Type Ia Supernovae (SNe Ia) sampling the redshift range 0 < z < 1.3. We find new evidence for a decrease with redshift in the strength of intermediate-mass element (IME) features, particularly Si II and to a lesser extent …
HD 100453: A Link Between Gas-Rich Protoplanetary Disks and Gas-Poor Debris Disks
Carmona, A.; Hamaguchi, K.; Henning, Th. +15 more
HD 100453 has an IR spectral energy distribution (SED) which can be fit with a power law plus a blackbody. Previous analysis of the SED suggests that the system is a young Herbig Ae star with a gas-rich, flared disk. We reexamine the evolutionary state of the HD 100453 system by refining its age (based on a candidate low-mass companion) and by exa…
Measuring Dust Production in the Small Magellanic Cloud Core-Collapse Supernova Remnant 1E 0102.2-7219
Sandstrom, Karin M.; Stanimirović, Snežana; Bolatto, Alberto D. +2 more
We present mid-infrared spectral mapping observations of the core-collapse supernova remnant 1E 0102.2-7219 in the Small Magellanic Cloud using the InfraRed Spectrograph on the Spitzer Space Telescope. The remnant shows emission from fine structure transitions of neon and oxygen as well as continuum emission from dust. Comparison of the mid-IR dus…