Search Publications
High-resolution Near-infrared Imaging of Submillimeter Galaxies
Lutz, Dieter; Baker, Andrew J.; Tacconi, Linda J. +2 more
We present F110W (~J) and F160W (~H) observations of 10 submillimeter galaxies (SMGs) obtained with the Hubble Space Telescope's (HST's) NICMOS camera. Our targets have optical redshifts in the range 2.20 <= z <= 2.81 confirmed by millimeter CO or mid-IR spectroscopy, guaranteeing that the two bands sample the rest-frame optical with the Bal…
The Future of the Sun: An Evolved Solar Twin Revealed by CoRoT
Porto de Mello, G. F.; Castro, M.; da Costa, J. S. +3 more
The question of whether the Sun is peculiar within the class of solar-type stars has been the subject of active investigation over the past three decades. Although several solar twins have been found with stellar parameters similar to those of the Sun (albeit in a range of Li abundances and with somewhat different compositions), their rotation per…
X-Ray Absorption of High-redshift Quasars
Behar, Ehud; Eitan, Assaf
The soft X-ray photoelectric absorption of high-z quasars has been known for two decades, but has no unambiguous astrophysical context. We construct the largest sample to date of 58 high-redshift quasars (z > 0.45) selected from the XMM-Newton archive based on a high photon count criterion (>1800). We measure the optical depth τ at 0.5 keV a…
Doppler Shifts in Active Region Moss Using SOHO/SUMER
Del Zanna, Giulio; Tripathi, Durgesh; Mason, Helen E. +1 more
The velocity of the plasma at the footpoint of hot loops in active region cores can be used to discriminate between different heating frequencies. Velocities on the order of a few kilometers per second would indicate low-frequency heating on sub-resolution strands, while velocities close to zero would indicate high-frequency (steady) heating. To d…
The Effect of UV/Soft X-Ray Excess Emission on the Warm Absorber Properties of Active Galactic Nuclei—A Case Study of IRAS 13349+2438
Dewangan, Gulab C.; Laha, Sibasish; Chakravorty, Susmita +1 more
The ultraviolet (UV) to X-ray continuum of active galactic nuclei (AGNs) is important for maintaining the ionization and thermal balance of the warm absorbers (WAs). However, the spectra in the sensitive energy range ~13.6-300 eV are unobservable due to Galactic extinction. Moreover, many AGNs show soft X-ray excess emission of varying strength in…
An External Origin for Carbon Monoxide on Uranus from Herschel/SPIRE?
Irwin, P. G. J.; Teanby, N. A.
Previous studies have demonstrated an external source of CO on Jupiter, Saturn, and Neptune. However, it has not been possible to demonstrate this on Uranus because of its low CO abundance, low upper-tropospheric temperatures, and low stratospheric thermal gradient, which make detection very challenging. Here we use 17 Herschel/SPIRE observation s…
A Spitzer Study of Pseudobulges in S0 Galaxies: Secular Evolution of Disks
Kembhavi, Ajit; Barway, Sudhanshu; Vaghmare, Kaustubh
In this Letter, we present a systematic study of lenticular (S0) galaxies based on mid-infrared imaging data on 185 objects taken using the Spitzer Infrared Array Camera. We identify the S0s hosting pseudobulges based on the position of the bulge on the Kormendy diagram and the Sérsic index of the bulge. We find that pseudobulges preferentially oc…
Decline and Recovery of the Interplanetary Magnetic Field during the Protracted Solar Minimum
Schwadron, Nathan A.; Smith, Charles W.; DeForest, Craig E.
The interplanetary magnetic field (IMF) is determined by the amount of solar magnetic flux that passes through the top of the solar corona into the heliosphere, and by the dynamical evolution of that flux. Recently, it has been argued that the total flux of the IMF evolves over the solar cycle due to a combination of flux that extends well outside…
Measurements of Cyclotron Features and Pulse Periods in the High-mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with the International Gamma-Ray Astrophysics Laboratory
Hemphill, Paul B.; Rothschild, Richard E.; Fürst, Felix +4 more
We present a spectral and timing analysis of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of two high-mass X-ray binaries, 4U 1538-522 and 4U 1907+09. Our timing measurements for 4U 1538-522 find the pulse period to have exhibited a spin-up trend until approximately 2009, after which there is evidence for a torque revers…
Suzaku View of the Swift/BAT Active Galactic Nuclei. V. Torus Structure of Two Luminous Radio-loud Active Galactic Nuclei (3C 206 and PKS 0707-35)
Ueda, Yoshihiro; Terashima, Yuichi; Tombesi, Francesco +2 more
We present the results from broadband X-ray spectral analysis of 3C 206 and PKS 0707-35 with Suzaku and Swift/BAT, two of the most luminous unobscured and obscured radio-loud active galactic nuclei (AGNs) with hard X-ray luminosities of 1045.5 erg s-1 and 1044.9 erg s-1 (14-195 keV), respectively. Based …