Search Publications
NuSTAR Observations of X-Ray Bursts from the Magnetar 1E 1048.1-5937
An, Hongjun; Hailey, Charles J.; Mori, Kaya +13 more
We report the detection of eight bright X-ray bursts from the 6.5 s magnetar 1E 1048.1-5937, during a 2013 July observation campaign with the Nuclear Spectroscopic Telescope Array. We study the morphological and spectral properties of these bursts and their evolution with time. The bursts resulted in count rate increases by orders of magnitude, so…
Herschel Observations of Far-infrared Cooling Lines in Intermediate Redshift (Ultra)-luminous Infrared Galaxies
Valtchanov, I.; Bock, J. J.; Scott, D. +17 more
We report the first results from a spectroscopic survey of the [C II] 158 µm line from a sample of intermediate redshift (0.2 <z < 0.8) (ultra)-luminous infrared galaxies, (U)LIRGs (L IR > 1011.5 L ⊙), using the Spectral and Photometric Imaging REceiver-Fourier Transform Spectrometer on board the Her…
Do Most Active Galactic Nuclei Live in High Star Formation Nuclear Cusps?
Koss, Michael; Mushotzky, Richard F.; Meléndez, Marcio +1 more
We present early results of the Herschel PACS (70 and 160 µm) and SPIRE (250, 350, and 500 µm) survey of 313 low redshift (z < 0.05), ultra-hard X-ray (14-195 keV) selected active galactic nuclei (AGNs) from the 58 month Swift/Burst Alert Telescope catalog. Selection of AGNs from ultra-hard X-rays avoids bias from obscuration, provi…
NGC 1365: A Low Column Density State Unveiling a Low Ionization Disk Wind
Porquet, D.; Reeves, J. N.; Braito, V. +3 more
We present the time-resolved spectral analysis of the XMM-Newton data of NGC 1365 collected during one XMM-Newton observation, which caught this "changing-look" active galactic nucleus in a high flux state characterized also by a low column density (N H ~ 1022 cm-2) of the X-ray absorber. During this observation, t…
Kiloparsec-scale Properties of Emission-line Galaxies
Papovich, Casey; Ferguson, Henry C.; Koekemoer, Anton M. +6 more
We perform a detailed study of the resolved properties of emission-line galaxies at kiloparsec scales to investigate how small-scale and global properties of galaxies are related. We use a sample of 119 galaxies in the GOODS fields. The galaxies are selected to cover a wide range in morphologies over the redshift range 0.2 < z < 1.3. High re…
Expansion of Hydrogen-poor Knots in the Born-again Planetary Nebulae A30 and A78
Gruendl, R. A.; Hamann, W. -R.; Chu, Y. -H. +8 more
We analyze the expansion of hydrogen-poor knots and filaments in the born-again planetary nebulae A30 and A78 based on Hubble Space Telescope (HST) images obtained almost 20 yr apart. The proper motion of these features generally increases with distance to the central star, but the fractional expansion decreases, i.e., the expansion is not homolog…
A Rare Encounter with Very Massive Stars in NGC 3125-A1
Leitherer, Claus; Chandar, Rupali; Wofford, Aida +1 more
Super star cluster A1 in the nearby starburst galaxy NGC 3125 is characterized by broad He II λ1640 emission (FWHM ~ 1200 km s-1) of unprecedented strength (equivalent width, EW = 7.1 ± 0.4 Å). Previous attempts to characterize the massive star content in NGC 3125-A1 were hampered by the low resolution of the UV spectrum and the lack of…
Big Fish in Small Ponds: Massive Stars in the Low-mass Clusters of M83
O'Connell, R. W.; Calzetti, D.; Kennicutt, R. C. +8 more
We have used multi-wavelength Hubble Space Telescope WFC3 data of the starbursting spiral galaxy M83 in order to measure variations in the upper end of the stellar initial mass function (uIMF) using the production rate of ionizing photons in unresolved clusters with ages <= 8 Myr. As in earlier papers on M51 and NGC 4214, the uIMF in M83 is con…
Extreme Conditions in a Close Analog to the Young Solar System: Herschel Observations of epsilon Eridani
Walker, H. J.; Ivison, R. J.; Fridlund, M. +22 more
Far-infrared Herschel images of the epsilon Eridani system, seen at a fifth of the Sun's present age, resolve two belts of debris emission. Fits to the 160 µm PACS image yield radial spans for these belts of 12-16 and 54-68 AU. The south end of the outer belt is ≈10% brighter than the north end in the PACS+SPIRE images at 160, 250, and 350 &…
Multifrequency Studies of the Peculiar Quasar 4C +21.35 during the 2010 Flaring Activity
Maraschi, L.; Troja, E.; Covino, S. +289 more
The discovery of rapidly variable Very High Energy (VHE; E > 100 GeV) γ-ray emission from 4C +21.35 (PKS 1222+216) by MAGIC on 2010 June 17, triggered by the high activity detected by the Fermi Large Area Telescope (LAT) in high energy (HE; E > 100 MeV) γ-rays, poses intriguing questions on the location of the γ-ray emitting region in this f…