Now showing items 1-20 of 23

• #### BAT Slew Survey (BATSS): Slew Data Analysis for the Swift-BAT Coded Aperture Imaging Telescope ﻿

(2013-03-18)
The BAT Slew Survey (BATSS) is the first wide-field survey of the hard X-ray sky (15–150 keV) with a slewing coded aperture imaging telescope. Its fine time resolution, high sensitivity and large sky coverage make it ...
• #### Cataclysmic Variables Discovered in the Chandra Multi-Wavelength Plane Survey ﻿

(Fabrizio Serra editore, 2013)
We present 25 cataclysmic variables discovered in the Chandra Multi-wavelength Plane Survey (ChaMPlane: Grindlay et al. (2005); Hong et al. (2005); Zhao et al. (2005)), which is designed to investigate the nature of the ...
• #### Chasing the Identification of ASCA Galactic Objects (ChIcAGO) - An X-ray Survey of Unidentified Sources in the Galactic Plane I: Source Sample and Initial Results ﻿

(IOP Publishing, 2014)
We present the Chasing the Identification of ASCA Galactic Objects (ChIcAGO) survey, which is designed to identify the unknown X-ray sources discovered during the ASCA Galactic Plane Survey (AGPS). Little is known about ...
• #### Discovery of near-ultraviolet counterparts to millisecond pulsars in the globular cluster 47 Tucanae ﻿

(Oxford University Press (OUP), 2015)
We report the discovery of the likely white dwarf companions to radio millisecond pulsars 47 Tuc Q and 47 Tuc S in the globular cluster 47 Tucanae. These blue stars were found in near-ultraviolet images from the Hubble ...
• #### Evidence for intermediate polars as the origin of the Galactic Center hard X-ray emission ﻿

(American Astronomical Society, 2016)
Recently, unresolved hard (20–40 keV) X-ray emission has been discovered within the central 10 pc of the Galaxy, possibly indicating a large population of intermediate polars (IPs). Chandra and XMM-Newton measurements in ...
• #### Exploring the Long-Term and Extreme Variability of Stars ﻿

(2012-08-23)
This thesis presents observational studies of long-term and extreme variability of stars with the Digital Access to a Sky Century@Harvard (DASCH) project. Stellar variations over decades are poorly explored. With the unique ...
• #### The high resolution X-ray imaging detector planes for the MIRAX mission ﻿

(IOP Publishing, 2013)
The MIRAX X-ray observatory, the first Brazilian-led astrophysics space mission, is designed to perform an unprecedented wide-field, wide-band hard X-ray (5–200 keV) survey of Galactic X-ray transient sources. In the ...
• #### The High-Metallicity Explosion Environment of the Relativistic Supernova 2009bb ﻿

(IOP Publishing, 2009)
We investigate the environment of the nearby (d ≈ 40 Mpc) broad-lined Type Ic supernova SN 2009bb. This event was observed to produce a relativistic outflow likely powered by a central accreting compact object. While such ...
• #### How I Learned to Stop Worrying and Love Eclipsing Binaries ﻿

(2015-09-01)
Relatively massive B-type stars with closely orbiting stellar companions can evolve to produce Type Ia supernovae, X-ray binaries, millisecond pulsars, mergers of neutron stars, gamma ray bursts, and sources of gravitational ...
• #### Identification of a Population of X-Ray-Emitting Massive Stars in the Galactic Plane ﻿

(IOP Publishing, 2011)
We present X-ray, infrared, optical, and radio observations of four previously unidentified Galactic plane X-ray sources: AX J163252-4746, AX J184738-0156, AX J144701-5919, and AX J144547-5931. Detection of each source ...
• #### Imaging Analysis of the Hard X-ray Telescope ProtoEXIST2 and New Techniques for High Resolution Coded Aperture Telescopes ﻿

(American Astronomical Society, 2016)
Wide-field (& 100 deg2) hard X-ray coded-aperture telescopes with high angular resolution (. 20) will enable a wide range of time domain astrophysics. For instance, transient sources such as gammaray bursts can be precisely ...
• #### Improved Mass and Radius Constraints for Quiescent Neutron Stars in Omega Cen and NGC 6397 ﻿

(Oxford University Press (OUP), 2014)
We use Chandra and XMM–Newton observations of the globular clusters ω Cen and NGC 6397 to measure the spectrum of their quiescent neutron stars (NSs), and thus to constrain the allowed ranges of mass and radius for each. ...
• #### Improved Photometry for the DASCH Pipeline ﻿

(University of Chicago Press, 2013)
The Digital Access to a Sky Century@Harvard (DASCH) project is digitizing the ∼500,000 glass plate images obtained (full sky) by the Harvard College Observatory from 1885 to 1992. Astrometry and photometry for each resolved ...
• #### Metamorphosis of Sn 2014c: Delayed Interaction Between a Hydrogen Poor Core-Collapse Supernova and a Nearby Circumstellar Shell ﻿

(IOP Publishing, 2015)
We present optical observations of supernova SN 2014C, which underwent an unprecedented slow metamorphosis from H-poor type Ib to H-rich type IIn over the course of one year. The observed spectroscopic evolution is consistent ...
• #### Multi-Wavelength Observations of the Radio Magnetar PSR J1622–4950 and Discovery of its Possibly Associated Supernova Remnant ﻿

(IOP Publishing, 2012)
We present multi-wavelength observations of the radio magnetar PSR J1622-4950 and its environment. Observations of PSR J1622-4950 with Chandra (in 2007 and 2009) and XMM (in 2011) show that the X-ray flux of PSR J1622-4950 ...
• #### The Nuclear Spectroscopic Telescope Array (NuSTAR) High-Energy X-Ray Mission ﻿

(IOP Publishing, 2013)
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in the band from 3 to 79 keV, extending the sensitivity of ...
• #### NuSTAR Hard X-ray Survey of the Galactic Center Region I: Hard X-ray Morphology and Spectroscopy of the Diffuse Emission ﻿

(IOP Publishing, 2015)
We present the first sub-arcminute images of the Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR J17456–2901 into non-thermal X-ray filaments, molecular clouds, point sources, ...
• #### NuSTAR Hard X-ray Survey of the Galactic Center Region II: X-ray Point Sources ﻿

(American Astronomical Society, 2016)
We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3–79 keV) X-ray point sources in a 0.6 deg${}^{2}$ region around Sgr A* with a total ...
• #### NuSTAR J163433-4738.7: A Fast X-Ray Transient in the Galactic Plane ﻿

(IOP Publishing, 2014)
During hard X-ray observations of the Norma spiral arm region by the Nuclear Spectroscopic Telescope Array (NuSTAR) in 2013 February, a new transient source, NuSTAR J163433-4738.7, was detected at a significance level of ...
• #### Optical spectroscopic observations of gamma-ray blazars candidates I: preliminary results ﻿

(IOP Publishing, 2014)
A significant fraction (~30%) of the γ-ray sources listed in the second Fermi/LAT (2FGL) catalog is still of unknown origin, being not yet associated with counterparts at lower energies. Using the available information at ...