Search Publications
On the Progenitor of the Type II-Plateau SN 2008cn in NGC 4603
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Foley, Ryan J. +7 more
A trend is emerging regarding the progenitor stars that give rise to the most common core-collapse supernovae (SNe), those of Type II-Plateau (II-P): they generally appear to be red supergiants with a limited range of initial masses, ~8-16 M sun. Here, we consider another example, SN 2008cn, in the nearly face-on spiral galaxy NGC 4603.…
Spectrophotometrically Identified Stars in the PEARS-N and PEARS-S Fields
Walsh, J. R.; Burgasser, A. J.; Bochanski, J. J. +9 more
Deep ACS slitless grism observations and identification of stellar sources are presented within the Great Observatories Origins Deep Survey North and South fields which were obtained in the Probing Evolution And Reionization Spectroscopically (PEARS) program. It is demonstrated that even low-resolution spectra can be a very powerful means of ident…
Role of Galaxy Mergers in Cosmic Star Formation History
Rieke, George; Shi, Yong; Lotz, Jennifer +1 more
We present a morphology study of intermediate-redshift (0.2 < z<1.2) luminous infrared galaxies (LIRGs) and general field galaxies in the GOODS fields using a revised asymmetry measurement method optimized for deep fields. By taking careful account of the importance of the underlying sky-background structures, our new method does not suffer …
Hard X-ray Emission in Kinking Filaments
Liu, Rui; Alexander, David
We present an observational study on the impact of the dynamic evolution of kinking filaments on the production of hard X-ray (HXR) emission. The investigation of two kinking-filament events in this paper, occurring on 2003 June 12 and 2004 November 10, respectively, combined with our earlier study on the failed filament eruption of 2002 May 27, s…
Suzaku Observations of the Circinus Galaxy
Yang, Y.; Matt, G.; Wilson, A. S. +2 more
We report Suzaku observations of the active, Compton-thick Circinus galaxy. Observations were obtained with both the X-ray imaging spectrometer (XIS) and the hard X-ray detector (HXD). Below 10 keV, the nuclear spectrum is dominated by radiation reflected from cold dense gas of high column density, while above 13 keV the radiation is directly tran…
Fe XIII Density Diagnostics in the EIS Observing Wavelengths
Young, P. R.; Hara, H.; Watanabe, T. +6 more
The diagnostic capability of Fe XIII line features seen in the 170-210 Å waveband of the EUV Imaging Spectrometer (EIS) on Hinode is investigated, with emphasis on density diagnostics applied to solar active regions. Four diagnostic line pairs are found to yield consistent densities ranging from 108.5 to 109.5 cm-3…
Upflows in Funnel-like Legs of Coronal Magnetic Loops
He, Jiansen; Tian, Hui; Marsch, Eckart +1 more
The prominent blueshifts of Ne VIII associated with the junctions of the magnetic network in the quiet Sun are still not well understood. By comparing the coronal magnetic-field structures as obtained by a potential-field reconstruction with the conspicuous blueshift patches on the Dopplergram of Ne VIII as observed in an equatorial quiet-Sun regi…
No Observational Constraints from Hypothetical Collisions of Hypothetical Dark Halo Primordial Black Holes with Galactic Objects
Qian, Lei; Abramowicz, Marek A.; Becker, Julia K. +3 more
It was suggested by several authors that hypothetical primordial black holes (PBHs) may contribute to the dark matter (DM) in our Galaxy. There are strong constraints based on the Hawking evaporation that practically exclude PBHs with masses m pbh ~ 1015to1016 g and smaller as significant contributors to the Galact…
The Extreme Star Formation Activity of Arp 299 Revealed by Spitzer IRS Spectral Mapping
Colina, Luis; Rieke, George H.; Alonso-Herrero, Almudena +6 more
We present Spitzer/IRS spectral mapping observations of the luminous infrared galaxy Arp 299 (IC 694 + NGC 3690) covering the central ~45'' ~ 9 kpc. The integrated mid-IR spectrum of Arp 299 is similar to that of local starbursts despite its strongly interacting nature and high-IR luminosity, L IR ~ 6 × 1011 L sun.…
Balancing the Cosmic Energy Budget: The Cosmic X-ray Background, Blazars, and the Compton Thick Active Galactic Nucleus Fraction
Ballantyne, D. R.; Draper, A. R.
At energies gsim2 keV, active galactic nuclei (AGNs) are the source of the cosmic X-ray background (CXB). For AGN population synthesis models to replicate the peak region of the CXB (~30 keV), a highly obscured and therefore nearly invisible class of AGN, known as Compton thick (CT) AGN, must be assumed to contribute nearly a third of the CXB. In …