Publications (147)
A NICER View of PSR J12311411: A Complex Case
Tuomo Salmi, Julia S. Deneva, Paul S. Ray +16
Recent constraints on neutron star mass and radius have advanced our understanding of the equation of state (EOS) of cold dense matter. Some of them have been obtained by modeling…
Disk Diffusion Propagation Model for the Outburst of XTE J1118+480
Kent S. Wood, Lev Titarchuk, Paul S. Ray +3
We present a linear diffusion model for the evolution of the double-peaked outburst in the transient source XTEJ1118+480. The model treats the two outbursts as episodic mass deposi…
Circularly polarized emission from the transient bursting radio source GCRT J1745-3009
Subhashis Roy, Scott D. Hyman, Sabyasachi Pal +3
We report detection of strong circularly polarized emission from the transient bursting source GCRT J1745-3009 based on new analysis of 325 MHz GMRT observations conducted on 28 Se…
A month of monitoring the new magnetar Swift J1555.2-5402 during an X-ray outburst
Teruaki Enoto, Mason Ng, Chin-ping Hu +23
The soft gamma-ray repeater Swift J1555.2-5402 was discovered by means of a 12-ms duration short burst detected with Swift BAT on 2021 June 3. Then 1.6 hours after the first burst…
The long-term evolution of the spin, pulse shape, and orbit of the accretion-powered millisecond pulsar SAX J1808.4-3658
Jacob M. Hartman, Alessandro Patruno, Deepto Chakrabarty +6
We present a 7 yr timing study of the 2.5 ms X-ray pulsar SAX J1808.4-3658, an X-ray transient with a recurrence time of ~2 yr, using data from the Rossi X-ray Timing Explorer cove…
The Radius of the High-mass Pulsar PSR J0740+6620 with 3.6 yr of NICER Data
Tuomo Salmi, Devarshi Choudhury, Yves Kini +14
We report an updated analysis of the radius, mass, and heated surface regions of the massive pulsar PSR J0740+6620 using Neutron Star Interior Composition Explorer (NICER) data fro…
Searching For Gravitational Waves From Cosmological Phase Transitions With The NANOGrav 12.5-year dataset
Zaven Arzoumanian, Paul T. Baker, Harsha Blumer +62
We search for a first-order phase transition gravitational wave signal in 45 pulsars from the NANOGrav 12.5 year dataset. We find that the data can be modeled in terms of a strong…
The Long Wavelength Array Software Library
Jayce Dowell, Daniel Wood, Kevin Stovall +3
The Long Wavelength Array Software Library (LSL) is a Python module that provides a collection of utilities to analyze and export data collected at the first station of the Long Wa…
Sharp Periodic Flares and Long-Term Variability in the High-Mass X-ray Binary XTE J1829-098 from RXTE PCA, Swift BAT and MAXI Observations
Robin H. D. Corbet, Ralf Ballhausen, Peter A. Becker +20
XTE J1829-098 is a transient X-ray pulsar with a period of ~7.8 s. It is a candidate Be star system, although the evidence for this is not yet definitive. We investigated the twent…
A NICER View of the Massive Pulsar PSR J0740+6620 Informed by Radio Timing and XMM-Newton Spectroscopy
Thomas E. Riley, Anna L. Watts, Paul S. Ray +27
We report on Bayesian estimation of the radius, mass, and hot surface regions of the massive millisecond pulsar PSR J07406620, conditional on pulse-profile modeling of Neutron S…
Long-term X-ray monitoring of LS I +61 303: analysis of spectral variability and flares
Jian Li, Diego F. Torres, Shu Zhang +6
We report on the full analysis of a Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) monitoring of the γ-ray binary system LS I +61 303. The data set covers 42…
Pulsar Timing with the Fermi LAT
Paul S. Ray, Matthew Kerr, Damien Parent +1
We present an overview of precise pulsar timing using data from the Large Area Telescope (LAT) on Fermi. We describe the analysis techniques including a maximum likelihood method f…
A NICER View of PSR J0030+0451: Updated Constraints from Six Years of NICER Observations
Yves Kini, Lucien Mauviard, Tuomo Salmi +13
Pulse-profile modeling of rotation-powered millisecond pulsars targeted by NICER has enabled mass--radius constraints of several neutron star sources, with implications for the den…
Discovery of PSR J1227-4853: A transition from a low-mass X-ray binary to a redback millisecond pulsar
Jayanta Roy, Paul S. Ray, Bhaswati Bhattacharyya +12
XSS J12270-4859 is an X-ray binary associated with the Fermi LAT gamma-ray source 1FGL J1227.9-4852. In 2012 December, this source underwent a transition where the X-ray and optica…
NICER Observation of the Temporal and Spectral Evolution of Swift J1818.0-1607: a Missing Link between Magnetars and Rotation Powered Pulsars
Chin-Ping Hu, Beste Begicarslan, Tolga Guver +13
We report on the hard X-ray burst and the first ~100 days NICER monitoring of the soft X-ray temporal and spectral evolution of the newly-discovered magnetar Swift J1818.0-1607. Th…
A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation
Thomas E. Riley, Anna L. Watts, Slavko Bogdanov +13
We report on Bayesian parameter estimation of the mass and equatorial radius of the millisecond pulsar PSR J00300451, conditional on pulse-profile modeling of Neutron Star Inter…
A wide-band, active antenna system for long wavelength radio astronomy
Brian C. Hicks, Nagini Paravastu-Dalal, Kenneth P. Stewart +9
We describe an "active" antenna system for HF/VHF (long wavelength) radio astronomy that has been successfully deployed 256-fold as the first station (LWA1) of the planned Long Wav…
Unveiling properties of the non-thermal X-ray production in the gamma-ray binary LS 5039 using the long-term pattern of its fast X-ray variability
Hiroki Yoneda, Valenti Bosch-Ramon, Teruaki Enoto +5
Gamma-ray binary systems, a subclass of high-mass X-ray binaries, show non-thermal emissions from radio to TeV. While efficient electron acceleration is considered to take place in…
GCRT J1742-3001: A New Radio Transient Towards the Galactic Center
Scott D. Hyman, Rudy Wijnands, T. Joseph W. Lazio +4
We report the detection of a new transient radio source, GCRT J1742-3001, located ~1 degree from the Galactic center. The source was detected ten times from late 2006 to 2007 May i…
How to Detect an Astrophysical Nanohertz Gravitational-Wave Background
Bence Bécsy, Neil J. Cornish, Patrick M. Meyers +93
Analysis of pulsar timing data have provided evidence for a stochastic gravitational wave background in the nHz frequency band. The most plausible source of such a background is th…
The NANOGrav 15-year Data Set: Search for Gravitational Wave Memory
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +102
We present the results of a search for nonlinear gravitational wave memory in the NANOGrav 15-year data set. We find no significant evidence for memory signals in the dataset, with…
The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +111
We report multiple lines of evidence for a stochastic signal that is correlated among 67 pulsars from the 15-year pulsar-timing data set collected by the North American Nanohertz O…
Astrophysics Milestones For Pulsar Timing Array Gravitational Wave Detection
Nihan S. Pol, Stephen R. Taylor, Luke Zoltan Kelley +49
The NANOGrav Collaboration reported strong Bayesian evidence for a common-spectrum stochastic process in its 12.5-yr pulsar timing array dataset, with median characteristic strain…
Multi-Messenger Gravitational Wave Searches with Pulsar Timing Arrays: Application to 3C66B Using the NANOGrav 11-year Data Set
Zaven Arzoumanian, Paul T. Baker, Adam Brazier +56
When galaxies merge, the supermassive black holes in their centers may form binaries and, during the process of merger, emit low-frequency gravitational radiation in the process. I…
STROBE-X High Energy Modular Array (HEMA)
Anthony L. Hutcheson, Marco Feroci, Andrea Argan +64
The High Energy Modular Array (HEMA) is one of three instruments that compose the STROBE-X mission concept. The HEMA is a large-area, high-throughput non-imaging pointed instrument…
Enhanced X-ray Emission Coinciding with Giant Radio Pulses from the Crab Pulsar
Teruaki Enoto, Toshio Terasawa, Shota Kisaka +34
Giant radio pulses (GRPs) are sporadic bursts emitted by some pulsars, lasting a few microseconds. GRPs are hundreds to thousands of times brighter than regular pulses from these s…
Timing six energetic rotation-powered X-ray pulsars, including the fast-spinning young PSR J0058-7218 and Big Glitcher PSR J0537-6910
Wynn C. G. Ho, Lucien Kuiper, Cristobal M. Espinoza +14
Measuring a pulsar's rotational evolution is crucial to understanding the nature of the pulsar. Here we provide updated timing models for the rotational evolution of six pulsars, f…
The GMRT High Resolution Southern Sky Survey for pulsars and transients -- III: searching for long period pulsars
Shubham Singh, Jayanta Roy, Ujjwal Panda +5
Searching for periodic non-accelerated signals in presence of ideal white noise using the fully phase-coherent Fast Folding Algorithm (FFA) is theoretically established as a more s…
A New Radio Detection of the Bursting Source GCRT J1745-3009
Scott D. Hyman, T. Joseph W. Lazio, Subhashis Roy +2
GCRT J1745-3009 is a transient bursting radio source located in the direction of the Galactic center, discovered in 330 MHz VLA observations from 2002 September 30--October 1 by Hy…
The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +102
Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15-year pulsar-timing data set compiled by the NANOGrav collaboration. Similar signals have been…
The NANOGrav 12.5-year Data Set: Chromatic Noise Characterization & Mitigation with Time-Domain Kernels
Jeffrey S. Hazboun, Joseph Simon, Jeremy Baier +64
Pulsar timing arrays (PTAs) have recently entered the detection era, quickly moving beyond the goal of simply improving sensitivity at the lowest frequencies for the sake of observ…
The Advanced X-ray Timing Array (AXTAR): A US MIDEX Mission Concept
Paul S. Ray, Bernard F. Phlips, Kent S. Wood +3
AXTAR is a NASA MIDEX mission concept for X-ray timing of compact objects that combines very large collecting area, broadband spectral coverage, high time resolution, highly flexib…
Pulse Profile Variability of PSR J1022+1001 in NANOGrav Data
William Fiore, Maura A. McLaughlin, Gabriella Agazie +46
Pulse profile stability is a central assumption of standard pulsar timing methods. Thus, it is important for pulsar timing array experiments such as the North American Nanohertz Ob…
The NANOGrav 15 yr Data Set: Looking for Signs of Discreteness in the Gravitational-wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +97
The cosmic merger history of supermassive black hole binaries (SMBHBs) is expected to produce a low-frequency gravitational wave background (GWB). Here we investigate how signs of…
A Detection of Red Noise in PSR J18242452A and Projections for PSR B1937+21 using NICER X-ray Timing Data
Jeffrey S. Hazboun, Jack Crump, Andrea N. Lommen +17
We have used X-ray data from the Neutron Star Interior Composition Explorer (NICER) to search for long time-scale, correlated variations ("red noise") in the pulse times of arrival…
The NANOGrav 11-year Data Set: High-precision timing of 45 Millisecond Pulsars
Zaven Arzoumanian, Adam Brazier, Sarah Burke-Spolaor +53
We present high-precision timing data over time spans of up to 11 years for 45 millisecond pulsars observed as part of the North American Nanohertz Observatory for Gravitational Wa…
A multi-wavelength study of nearby millisecond pulsar PSR J14001431: improved astrometry & an optical detection of its cool white dwarf companion
Joseph K. Swiggum, David L. Kaplan, Maura A. McLaughlin +16
In 2012, five high school students involved in the Pulsar Search Collaboratory discovered the millisecond pulsar PSR J14001431 and initial timing parameters were published in Ro…
Understanding the Neutron Star Population with the SKA
Thomas M. Tauris, Victoria M. Kaspi, Rene P. Breton +9
Since their discovery in the late 1960's the population of known neutron stars (NSs) has grown to ~2500. The last five decades of observations have yielded many surprises and demon…
The NANOGrav 15-year Gravitational-Wave Background Methods
Aaron D. Johnson, Patrick M. Meyers, Paul T. Baker +93
Pulsar timing arrays (PTAs) use an array of millisecond pulsars to search for gravitational waves in the nanohertz regime in pulse time of arrival data. This paper presents rigorou…
Gravitational Wave Measurement of the - Intrinsic Scatter at High Redshift
Cayenne Matt, Kayhan Gültekin, Gabriella Agazie +109
The observed GWB spectrum is higher in amplitude than model predictions by a factor of 2-3. Using a semi-analytic model, we evaluate the effect of a high-scatter supermassive black…
Future Perspectives for Gamma-ray Burst Detection from Space
Enrico Bozzo, Lorenzo Amati, Wayne Baumgartner +35
Since their first discovery in the late 1960s, Gamma-ray bursts have attracted an exponentially growing interest from the international community due to their central role in the m…
The NANOGrav 15-year Data Set: Observations and Timing of 68 Millisecond Pulsars
Gabriella Agazie, Md Faisal Alam, Akash Anumarlapudi +97
We present observations and timing analyses of 68 millisecond pulsars (MSPs) comprising the 15-year data set of the North American Nanohertz Observatory for Gravitational Waves (NA…
A growing braking index and spin-down swings for the pulsar PSR B0540-69
Cristóbal M. Espinoza, Lucien Kuiper, Wynn C. G. Ho +5
The way pulsars spin down is not understood in detail, but a number of possible physical mechanisms produce a spin-down rate that scales as a power of the rotation rate ($\dotν\pr…
The Identification of the X-ray Counterpart to PSR J2021+4026
Martin C. Weisskopf, Roger W. Romani, Massimiliano Razzano +16
We report the probable identification of the X-ray counterpart to the gamma-ray pulsar PSR J2021+4026 using imaging with the Chandra X-ray Observatory ACIS and timing analysis with…
The NANOGrav 12.5-year Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
Zaven Arzoumanian, Paul T. Baker, Laura Blecha +75
Pulsar timing array collaborations, such as the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), are seeking to detect nanohertz gravitational waves emitted…
Shapiro Delay Measurements from Fifteen Years of PSR J12311411 Radio Observations
H. Thankful Cromartie, Matthew Kerr, Scott M. Ransom +5
We present 15 years of Nançay and Green Bank radio telescope timing observations for PSR J12311411. This millisecond pulsar is a primary science target for the Neutron Star Int…
The NANOGrav 15-year Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +96
Evidence for a low-frequency stochastic gravitational wave background has recently been reported based on analyses of pulsar timing array data. The most likely source of such a bac…
Discovery of Soft X-ray Pulsations from PSR J1231-1411 using NICER
Paul S. Ray, Sebastien Guillot, Scott M. Ransom +10
We report the discovery of soft X-ray pulsations from the nearby millisecond pulsar PSR J12311411 using NICER. The pulsed emission is characterized by a broad and asymmetric mai…
The NANOGrav 11yr Data Set: Limits on Supermassive Black Hole Binaries in Galaxies within 500Mpc
Zaven Arzoumanian, Paul T. Baker, Adam Brazier +54
Supermassive black hole binaries (SMBHBs) should form frequently in galactic nuclei as a result of galaxy mergers. At sub-parsec separations, binaries become strong sources of low-…
Multiwavelength Spectral Analysis and Neural Network Classification of Counterparts to 4FGL Unassociated Sources
Stephen Kerby, Amanpreet Kaur, Abraham D. Falcone +7
The Fermi-LAT unassociated sources represent some of the most enigmatic gamma-ray sources in the sky. Observations with the Swift-XRT and -UVOT telescopes have identified hundreds…
Constraining the Neutron Star Mass-Radius Relation and Dense Matter Equation of State with NICER. I. The Millisecond Pulsar X-ray Data Set
Slavko Bogdanov, Sebastien Guillot, Paul S. Ray +27
We present the set of deep Neutron Star Interior Composition Explorer (NICER) X-ray timing observations of the nearby rotation-powered millisecond pulsars PSRs J0437-4715, J0030+04…
Pulsar Results with the Fermi Large Area Telescope
Paul S. Ray, Pablo M. Saz Parkinson
The launch of the Fermi Gamma-ray Space Telescope has heralded a new era in the study of gamma-ray pulsars. The population of confirmed gamma-ray pulsars has gone from 6-7 to more…
Inference on inner galaxy structure via gravitational waves from supermassive binaries
Yifan Chen, Matthias Daniel, Daniel J. D'Orazio +107
The detection of a stochastic gravitational wave background by pulsar-timing arrays indicates the presence of a population of supermassive black hole binaries. Although the observe…
CHIME-o-Grav: Wideband Timing of Four Millisecond Pulsars from the NANOGrav 15-yr dataset
Gabriella Agazie, David L. Kaplan, Abhimanyu Susobhanan +50
Wideband timing of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) datasets, where a single time-of-arrival (TOA) and a single dispersion measure (DM) a…
The NANOGrav 15-Year Data Set: Detector Characterization and Noise Budget
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +88
Pulsar timing arrays (PTAs) are galactic-scale gravitational wave detectors. Each individual arm, composed of a millisecond pulsar, a radio telescope, and a kiloparsecs-long path,…
A Strong X-Ray Burst from the Low Mass X-Ray Binary EXO0748-676
Michael T. Wolff, Peter A. Becker, Paul S. Ray +1
We have observed an unusually strong X-ray burst as a part of our regular eclipse timing observations of the low mass binary system EXO0748-676. The burst peak flux was 5.2x10^-8 e…
The Radius of PSR J0740+6620 from NICER with NICER Background Estimates
Tuomo Salmi, Serena Vinciguerra, Devarshi Choudhury +15
We report a revised analysis for the radius, mass, and hot surface regions of the massive millisecond pulsar PSR J0740+6620, studied previously with joint fits to NICER and XMM-New…
The STROBE-X Low Energy Modular Array (LEMA) Instrument
Keith C. Gendreau, Dominic Maes, Ronald A. Remillard +4
The Low Energy Modular Array (LEMA) is one of three instruments that compose the STROBE-X mission concept. The LEMA is a large effective-area, high throughput, non-imaging pointed…
Variability in the orbital profiles of the X-ray emission of the gamma-ray binary LS I +61 303
Diego F. Torres, Shu Zhang, Jian Li +6
We report on the analysis of Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) monitoring observations of the -ray binary system LS I +61 303, covering 35 ful…
A NICER view of the 1.4 solar-mass edge-on pulsar PSR J0614-3329
Lucien Mauviard, Sebastien Guillot, Tuomo Salmi +20
Four neutron star radius measurements have already been obtained by modeling the X-ray pulses of rotation-powered millisecond pulsars observed by the Neutron Star Interior Composit…
The Black Hole Candidate Swift J1728.93613 and the Supernova Remnant G351.90.9
Mayura Balakrishnan, Paul A. Draghis, Jon M. Miller +12
A number of neutron stars have been observed within the remnants of the core-collapse supernova explosions that created them. In contrast, black holes are not yet clearly associate…
An updated mass-radius analysis of the 2017-2018 NICER data set of PSR J0030+0451
Serena Vinciguerra, Tuomo Salmi, Anna L. Watts +11
In 2019 the NICER collaboration published the first mass and radius inferred for PSR J0030+0451, thanks to NICER observations, and consequent constraints on the equation of state c…
The NANOGrav 15 yr Data Set: Chromatic Gaussian Process Noise Models for Six Pulsars
Bjorn Larsen, Chiara M. F. Mingarelli, Jeffrey S. Hazboun +61
Pulsar timing arrays (PTAs) are designed to detect low-frequency gravitational waves (GWs). GWs induce achromatic signals in PTA data, meaning that the timing delays do not depend…
STROBE-X: A probe-class mission for X-ray spectroscopy and timing on timescales from microseconds to years
Paul S. Ray, Zaven Arzoumanian, Søren Brandt +30
We describe the Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X), a probe-class mission concept that will provide an unprecedented view of the X-ray…
Characterization of Pulsar Sources for X-ray Navigation
Paul S. Ray, Kent S. Wood, Michael T. Wolff
The Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) is a technology demonstration enhancement to the Neutron Star Interior Composition Explorer (NICER) missio…
The NANOGrav 15-Year Data Set: Improved Timing Precision With VLBI Astrometric Priors
Sofia V. Sosa Fiscella, Michael T. Lam, Gabriella Agazie +47
Accurate pulsar astrometric estimates play an essential role in almost all high-precision pulsar timing experiments. Traditional pulsar timing techniques refine these estimates by…
An XTE Archival Search for Coherent X-ray Pulsations in LMXB 4U 1820-30
Rim Dib, Scott M. Ransom, Paul S. Ray +2
As part of a large-scale search for coherent pulsations from LMXBs in the RXTE archive, we have completed a detailed series of searches for coherent pulsations of 4U 1820-30 -- an…
A NICER view of PSR J0030+0451: evidence for a global-scale multipolar magnetic field
Anna V. Bilous, Anna L. Watts, Alice K. Harding +8
Recent modeling of NICER observations of thermal X-ray pulsations from the surface of the isolated millisecond pulsar PSR J0030+0451 suggests that the hot emitting regions on the p…
The NANOGrav 12.5-year Data Set: Search for Gravitational Wave Memory
Gabriella Agazie, Zaven Arzoumanian, Paul T. Baker +87
We present the results of a Bayesian search for gravitational wave (GW) memory in the NANOGrav 12.5-yr data set. We find no convincing evidence for any gravitational wave memory si…
The NANOGrav 15 yr Data Set: Running of the Spectral Index
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +102
The NANOGrav 15-year data provides compelling evidence for a stochastic gravitational-wave (GW) background at nanohertz frequencies. The simplest model-independent approach to char…
Rapid spin changes around a magnetar fast radio burst
Chin-Ping Hu, Takuto Narita, Teruaki Enoto +12
Magnetars are neutron stars with extremely high magnetic fields that exhibit various X-ray phenomena such as sporadic sub-second bursts, long-term persistent flux enhancements, and…
A Highly Eccentric 3.9-Millisecond Binary Pulsar in the Globular Cluster NGC 6652
Megan E. DeCesar, Scott M. Ransom, David L. Kaplan +2
We present the Robert C. Byrd Green Bank Telescope discovery of the highly eccentric binary millisecond pulsar PSR J18353259A in the Fermi Large Area Telescope-detected globular…
A Bursting Radio Transient in the Direction of the Galactic Center
Paul S. Ray, Scott D. Hyman, T. Joseph Lazio +4
The radio sky is poorly sampled for rapidly varying transients because of the narrow field-of-view of most imaging radio telescopes at cm and shorter wavelengths. The emergence of…
Discovery, Timing, and Multiwavelength Observations of the Black Widow Millisecond Pulsar PSR J1555-2908
Paul S. Ray, Lars Nieder, Colin J. Clark +21
We report the discovery of PSR J1555-2908, a 1.79 ms radio and gamma-ray pulsar in a 5.6 hr binary system with a minimum companion mass of 0.052 . This fast and energetic…
Possible Magnetic Activity in the Low Mass X-ray Binary EXO 0748-676
Michael T. Wolff, Kent S. Wood, Paul S. Ray
We report evidence of magnetic activity associated with the secondary star in the EXO 0748-676 low mass X-ray binary system. An analysis of a sequence of five consecutive X-ray ecl…
X-Ray Studies of Redbacks
Mallory S. E. Roberts, Maura A. McLaughlin, Peter A. Gentile +3
We consider the X-ray properties of the redback class of eclipsing millisecond pulsars. These are transitional systems between accreting low-mass X-ray binaries and binary millisec…
Front-End ASIC for the STROBE-X HEMA and WFM Detectors: Concept and Design
Gianluigi De Geronimo, Paul S. Ray, Eric A. Wulf +6
This paper presents the NSX front-end ASIC, being developed to read charge signals from the HEMA and WFM X-ray detectors for the STROBE-X mission. The ASIC reads out signals from u…
H-alpha Emission Variability in the gamma-ray Binary LS I +61 303
M. Virginia McSwain, Erika D. Grundstrom, Douglas R. Gies +1
LS I +61 303 is an exceptionally rare example of a high mass X-ray binary (HMXB) that also exhibits MeV-TeV emission, making it one of only a handful of "gamma-ray binaries". Here…
Bright X-ray and Radio Pulses from a Recently Reactivated Magnetar
Aaron B. Pearlman, Walid A. Majid, Thomas A. Prince +9
Magnetars are young, rotating neutron stars that possess larger magnetic fields ( - G) and longer rotational periods ( 1-12 s) than ordi…
The NANOGrav 12.5-year Data Set: Wideband Timing of 47 Millisecond Pulsars
Md F. Alam, Zaven Arzoumanian, Paul T. Baker +67
We present a new analysis of the profile data from the 47 millisecond pulsars comprising the 12.5-year data set of the North American Nanohertz Observatory for Gravitational Waves…
The NANOGrav 15 yr Data Set: Targeted Searches for Supermassive Black Hole Binaries
Nikita Agarwal, Gabriella Agazie, Akash Anumarlapudi +116
We present the first targeted searches for continuous gravitational waves (CWs) from 114 active galactic nuclei (AGN) that may host supermassive black hole binaries, using the NANO…
The NANOGrav 15 yr data set: Posterior predictive checks for gravitational-wave detection with pulsar timing arrays
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +99
Pulsar-timing-array experiments have reported evidence for a stochastic background of nanohertz gravitational waves consistent with the signal expected from a population of superma…
The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
Zaven Arzoumanian, Paul T. Baker, Harsha Blumer +58
We search for an isotropic stochastic gravitational-wave background (GWB) in the -year pulsar timing data set collected by the North American Nanohertz Observatory for Gravit…
FAST discovery of an extremely radio-faint millisecond pulsar from the Fermi-LAT unassociated source 3FGL J0318.1+0252
Pei Wang, Di Li, Colin J. Clark +23
High sensitivity radio searches of unassociated -ray sources have proven to be an effective way of finding new pulsars. Using the Five-hundred-meter Aperture Spherical radio Te…
The STROBE-X Wide Field Monitor Instrument
Ronald A. Remillard, Margarita Hernanz, Jean in 't Zand +26
The Wide Field Monitor (WFM) is one of the three instruments on the Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) mission, which was proposed in r…
The Anomalous Acceleration of PSR J2043+1711: Long-Period Orbital Companion or Stellar Flyby?
Thomas Donlon, Sukanya Chakrabarti, Michael T. Lam +53
Based on the rate of change of its orbital period, PSR J2043+1711 has a substantial peculiar acceleration of 3.5 0.8 mm/s/yr, which deviates from the acceleration predicted b…
Timing the pulsations of the accreting millisecond pulsar SAX J1808.4-3658 during its 2019 outburst
Peter Bult, Deepto Chakrabarty, Zaven Arzoumanian +5
In this paper we present a coherent timing analysis of the 401 Hz pulsations of the accreting millisecond X-ray pulsar SAX J1808.4-3658 during its 2019 outburst. Using observations…
A search for extragalactic pulsars in the Local Group galaxies IC 10 and Barnard's Galaxy
Hind Al Noori, Mallory S. E. Roberts, David Champion +3
As of today, more than 2500 pulsars have been found, nearly all in the Milky Way, with the exception of ~28 pulsars in the Small and Large Magellanic Clouds. However, there have be…
The GMRT High Resolution Southern Sky Survey for pulsars and transients -I. Survey description and initial discoveries
Bhaswati Bhattacharyya, Sally Cooper, Mateusz Malenta +8
We are conducting a survey for pulsars and transients using the Giant Metrewave Radio Telescope (GMRT). The GMRT High Resolution Southern Sky (GHRSS) survey is an off-Galactic-plan…
The NANOGrav 15 yr and 20 yr Datasets: Timing Events and Pulse Shape Changes
Ben Jacobson-Bell, James M. Cordes, Shami Chatterjee +61
The average pulse shape of a pulsar is typically stable over decadal timescales, enabling estimation of pulse times of arrival to better than a small fraction of the pulse width us…
PINT: A Modern Software Package for Pulsar Timing
Jing Luo, Scott Ransom, Paul Demorest +13
Over the past few decades, the measurement precision of some pulsar-timing experiments has advanced from ~10 us to ~10 ns, revealing many subtle phenomena. Such high precision dema…
The NANOGrav 15-year data set: Search for Transverse Polarization Modes in the Gravitational-Wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +96
Recently we found compelling evidence for a gravitational wave background with Hellings and Downs (HD) correlations in our 15-year data set. These correlations describe gravitation…
X-Ray Eclipse Timing in the LMXB EXO0748-676
Michael T. Wolff, Paul S. Ray, Kent S. Wood
Orbital period changes are an important diagnostic for understanding low mass X-ray binary (LMXB) accretion-induced angular momentum exchange and overall system evolution. We prese…
Searching for Exotrojans in Pulsar Systems
Jackson D. Taylor, Emmanuel Fonseca, Lankeswar Dey +50
Trojan asteroids are found in the equilateral triangle Lagrange points of the Sun-Jupiter system in great number, though they also exist less prolifically in other parts of the Sol…
The NANOGrav 15-year Data Set: Search for Anisotropy in the Gravitational-Wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +90
The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has reported evidence for the presence of an isotropic nanohertz gravitational wave background (GWB) in…
Return of the Big Glitcher: NICER timing and glitches of PSR J0537-6910
Wynn C. G. Ho, Cristobal M. Espinoza, Zaven Arzoumanian +7
PSR J0537-6910, also known as the Big Glitcher, is the most prolific glitching pulsar known, and its spin-induced pulsations are only detectable in X-ray. We present results from a…
Observation of X-ray variability in the BL Lac object 1ES1959+65
Berrie Giebels, Elliott D. Bloom, Warren Focke +15
This paper reports X-ray spectral observations of a relatively nearby z = 0.048 BL Lacertae (BL Lac) object 1ES1959+650, which is a potential TeV emitter. The observations include…
Bayesian Solar Wind Modeling with Pulsar Timing Arrays
Jeffrey S. Hazboun, Joseph Simon, Dustin R. Madison +27
Using Bayesian analyses we study the solar electron density with the NANOGrav 11-year pulsar timing array (PTA) dataset. Our model of the solar wind is incorporated into a global f…
Constraining the Neutron Star Mass--Radius Relation and Dense Matter Equation of State with NICER. III. Model Description and Verification of Parameter Estimation Codes
Slavko Bogdanov, Alexander J. Dittmann, Wynn C. G. Ho +16
We describe the X-ray pulse profile models we use, and how we use them, to analyze Neutron Star Interior Composition Explorer (NICER) observations of rotation-powered millisecond p…
Determining the Equation of State of Cold, Dense Matter with X-ray Observations of Neutron Stars
Slavko Bogdanov, Anna L. Watts, Deepto Chakrabarty +9
The unknown state of matter at ultra-high density, large proton/neutron number asymmetry, and low temperature is a major long-standing problem in modern physics. Neutron stars prov…