Search Publications
A New Diagnostic of Active Galactic Nuclei: Revealing Highly Absorbed Systems at Redshift >0.3
Dickinson, Mark; Juneau, Stéphanie; Salim, Samir +1 more
We introduce the Mass-Excitation (MEx) diagnostic to identify active galactic nuclei (AGNs) in galaxies at intermediate redshift. In the absence of near-infrared spectroscopy, necessary for using traditional nebular line diagrams at z > 0.4, we demonstrate that combining [O III] λ5007/Hβ and stellar mass successfully distinguishes between star …
Discovery of the nearby long, soft GRB 100316D with an associated supernova
Sakamoto, T.; Covino, S.; D'Avanzo, P. +43 more
We report the Swift discovery of the nearby long, soft gamma-ray burst GRB 100316D, and the subsequent unveiling of its low-redshift host galaxy and associated supernova. We derive the redshift of the event to be z= 0.0591 ± 0.0001 and provide accurate astrometry for the gamma-ray burst (GRB) supernova (SN). We study the extremely unusual prompt e…
A robust sample of galaxies at redshifts 6.0<z<8.7: stellar populations, star formation rates and stellar masses
Bowler, R. A. A.; McLure, R. J.; Dunlop, J. S. +7 more
We present the results of a photometric redshift analysis designed to identify z≥ 6 galaxies from the near-infrared Hubble Space Telescope imaging in three deep fields [Hubble Ultra Deep Field (HUDF), HUDF09-2 and Early Release Science] covering a total area of 45 square arcmin. By adopting a rigorous set of criteria for rejecting low-redshift int…
Young Planetary Nebulae: Hubble Space Telescope Imaging and a New Morphological Classification System
Morris, Mark R.; Sahai, Raghvendra; Villar, Gregory G.
Using Hubble Space Telescope images of 119 young planetary nebulae (PNs), most of which have not previously been published, we have devised a comprehensive morphological classification system for these objects. This system generalizes a recently devised system for pre-planetary nebulae, which are the immediate progenitors of PNs. Unlike previous c…
A mature cluster with X-ray emission at z = 2.07
Finoguenov, A.; Cimatti, A.; Daddi, E. +10 more
We report evidence of a fully established galaxy cluster at z = 2.07, consisting of a ~20σ overdensity of red, compact spheroidal galaxies spatially coinciding with extended X-ray emission detected with XMM-Newton. We use VLT VIMOS and FORS2 spectra and deep Subaru, VLT and Spitzer imaging to estimate the redshift of the structure from a prominent…
Polarized Gamma-Ray Emission from the Galactic Black Hole Cygnus X-1
Rodriguez, J.; Wilms, J.; Laurent, P. +3 more
Because of their inherently high flux allowing the detection of clear signals, black hole x-ray binaries are interesting candidates for polarization studies, even if no polarization signals have been observed from them before. Such measurements would provide further detailed insight into these sources’ emission mechanisms. We measured the polariza…
Far-infrared Line Deficits in Galaxies with Extreme L_{FIR}/M_{H_{2}} Ratios
Lutz, D.; Genzel, R.; Poglitsch, A. +13 more
We report initial results from the far-infrared fine structure line observations of a sample of 44 local starbursts, Seyfert galaxies, and infrared luminous galaxies obtained with the PACS spectrometer on board Herschel. We show that the ratio between the far-infrared luminosity and the molecular gas mass, {L_{FIR}/{M_{H_{2}}, is a much better pro…
Plasma Jet Braking: Energy Dissipation and Nonadiabatic Electrons
André, M.; Vaivads, A.; Owen, C. J. +2 more
We report in situ observations by the Cluster spacecraft of wave-particle interactions in a magnetic flux pileup region created by a magnetic reconnection outflow jet in Earth’s magnetotail. Two distinct regions of wave activity are identified: lower-hybrid drift waves at the front edge and whistler-mode waves inside the pileup region. The whistle…
Phase diagram for magnetic reconnection in heliophysical, astrophysical, and laboratory plasmas
Ji, Hantao; Daughton, William
Recent progress in understanding the physics of magnetic reconnection is conveniently summarized in terms of a phase diagram which organizes the essential dynamics for a wide variety of applications in heliophysics, laboratory, and astrophysics. The two key dimensionless parameters are the Lundquist number and the macrosopic system size in units o…
The Yellow Supergiant Progenitor of the Type II Supernova 2011dh in M51
Sollerman, J.; Smartt, S. J.; Kotak, R. +11 more
We present the detection of the putative progenitor of the Type IIb SN 2011dh in archival pre-explosion Hubble Space Telescope images. Using post-explosion Adaptive Optics imaging with Gemini NIRI+ALTAIR, the position of the supernova (SN) in the pre-explosion images was determined to within 23 mas. The progenitor candidate is consistent with an F…