Search Publications
On Understanding the Nature of Collisions of Coronal Mass Ejections Observed by STEREO
Wang, Yuming; Srivastava, Nandita; Mishra, Wageesh
We attempt to understand the collision characteristics of two coronal mass ejections (CMEs) launched successively from the Sun on 2013 October 25. The estimated kinematics, from three-dimensional (3D) reconstruction techniques applied to observations of CMEs by the SECCHI/Coronagraphic (COR) and Heliospheric Imagers, reveal their collision around …
The rotational dynamics of Titan from Cassini RADAR images
Iess, Luciano; Mitri, Giuseppe; Meriggiola, Rachele +2 more
Between 2004 and 2009 the RADAR instrument of the Cassini mission provided 31 SAR images of Titan. We tracked the position of 160 surface landmarks as a function of time in order to monitor the rotational dynamics of Titan. We generated and processed RADAR observables using a least squares fit to determine the updated values of the rotational para…
The Evolution of Far-infrared CO Emission from Protostars
Henning, T.; Manoj, P.; Megeath, S. T. +7 more
We investigate the evolution of far-IR CO emission from protostars observed with Herschel/PACS for 50 sources from the combined sample of HOPS and DIGIT Herschel key programs. From the uniformly sampled spectral energy distributions, whose peaks are well sampled, we computed the {L}{bol}, {T}{bol}, and {L}{bol}/{L}…
The Geometry of the Infrared and X-Ray Obscurer in a Dusty Hyperluminous Quasar
Brandt, William N.; Koss, Michael; Ricci, Claudio +24 more
We study the geometry of the active galactic nucleus (AGN) obscurer in IRAS 09104+4109, an IR-luminous, radio-intermediate FR-I source at z = 0.442, using infrared data from Spitzer and Herschel, X-ray data from NuSTAR, Swift, Suzaku, and Chandra, and an optical spectrum from Palomar. The infrared data imply a total rest-frame 1-1000 µm lumi…
Ordinary X-Rays from Three Extraordinary Millisecond Pulsars: XMM-Newton Observations of PSRs J0337+1715, J0636+5129, and J0645+5158
Kaplan, David L.; Stairs, Ingrid; Spiewak, Renée +8 more
We present the first X-ray observations of three recently discovered millisecond pulsars (MSPs) with interesting characteristics: PSR J0337+1715, PSR J0636+5129, and PSR J0645+5158. PSR J0337+1715 is a fast-spinning, bright, and so-far unique MSP in a hierarchical triple system with two white dwarf companions. PSR J0636+5129 is an MSP in a very ti…
The ionization rates of galactic nuclei and disks from Herschel/HIFI observations of water and its associated ions
van der Tak, F. F. S.; Güsten, R.; Weiß, A. +1 more
Context. Dense gas in galactic nuclei is known to feed central starbursts and AGN, but the properties of this gas are poorly known because of the high obscuration by dust.
Aims: Submm-wave spectroscopy of water and its associated ions is useful to trace the oxygen chemistry of interstellar gas, in particular to constrain its ionization rate. …
Wind mass transfer in S-type symbiotic binaries. II. Indication of wind focusing
Skopal, A.; Shagatova, N.; Cariková, Z.
Context. The wind mass transfer from a giant to its white dwarf companion in symbiotic binaries is not well understood. For example, the efficiency of wind mass transfer of the canonical Bondi-Hoyle accretion mechanism is too low to power the typical luminosities of the accretors. However, recent observations and modelling indicate a considerably …
The Wide-angle Outflow of the Lensed z = 1.51 AGN HS 0810+2554
Cappi, M.; Chartas, G.; Giustini, M. +4 more
We present results from X-ray observations of the gravitationally lensed z = 1.51 active galactic nucleus (AGN) HS 0810+2554 performed with the Chandra X-ray Observatory and XMM-Newton. Blueshifted absorption lines are detected in both observations at rest-frame energies ranging between ∼1 and 12 keV at ≳99% confidence. The inferred velocities of …
Photometric and Astrometric Vagaries of the Enigma Star KIC 8462852
Makarov, Valeri V.; Goldin, Alexey
We apply a principal component analysis (PCA)-based pre-whitening method to the entire collection of main Kepler mission long-cadence data for KIC 8462852 spanning four years. This technique removes the correlated variations of instrumental origin in both the detected light curves and astrometry, resolving intrinsic changes in flux and image posit…
Hubble and Keck Telescope Observations of Active Asteroid 288P/300163 (2006 VW139)
Mutchler, Max; Jewitt, David; Agarwal, Jessica +2 more
We present Hubble Space Telescope (HST) and Keck 10 m telescope observations of active asteroid 288P/300163 (2006 VW139) taken to examine ejected dust. The nucleus is a C-type object with absolute magnitude HV = 17.0 ± 0.1 and estimated diameter ∼2.6 km (for assumed visual geometric albedo pV = 0.04). Variations in the bright…