Search Publications
Astrometric microlensing of primordial black holes with Gaia
Rentala, Vikram; Verma, Himanshu
The Gaia space telescope allows for unprecedented accuracy for astrometric measurements of stars in the Galaxy. In this work, we explore the sensitivity of Gaia to detect primordial black hole (PBH) dark matter through the distortions that PBHs would create in the apparent trajectories of background stars, an effect known as astrometric microlensi…
Exploring Stellar Cluster and Feedback-driven Star Formation in the Galactic Mid-infrared Bubble [HKS2019] E70
Pandey, Rakesh; Sharma, Saurabh; Dewangan, Lokesh +8 more
We present a comprehensive analysis of the Galactic mid-infrared bubble [HKS2019] E70 (E70) by adopting a multiwavelength approach to understand the physical environment and star formation scenario around it. We identified a small (radius ~1.7 pc) stellar cluster inside the E70 bubble, and its distance is estimated as 3.26 ± 0.45 kpc. This cluster…
The GW Vir Instability Strip in Light of New Observations of PG 1159 Stars: Discovery of Pulsations in the Central Star of A72 and Variability of RX J0122.9-7521
Jones, David; Karjalainen, Marie; Caldwell, John A. R. +9 more
We present the results of new time-series photometric observations of 29 pre-white dwarf stars of PG 1159 spectral type, carried out in the years 2014-2022. For the majority of stars, a median noise level in Fourier amplitude spectra of 0.5-1.0 mmag was achieved. This allowed the detection of pulsations in the central star of planetary nebula A72 …
A high-mass X-ray binary pulsar 4U 1907+09 with multiple absorption-line features in the spectrum
Tobrej, Mohammed; Rai, Binay; Ghising, Manoj +2 more
We report X-ray observations of the high mass X-ray binary (HMXB) pulsar 4U 1907+09. Spectral and timing analysis of the source has been performed using Nuclear Spectroscopic Telescope Array (NuSTAR) observation. Timing analysis of the photon events revealed the coherent X-ray pulsation of the source with a pulse period of 442.92 ± 0.03 s. It is o…
A Catalog of Young Stellar Objects from the LAMOST and ZTF Surveys
Zhang, Jingyi; Zhang, Yanxia; Kang, Zihan +2 more
As astronomical data sets become too large for traditional analysis approaches, more machine-learning algorithms are employed in astronomy. A wealth of light variation data have been accumulated, which provide rich samples for astronomers to study variable stars. Facing the challenge of big data, this article takes the classification of variable a…
Solar activity relations in energetic electron events measured by the MESSENGER mission
Lario, D.; Rodríguez-Pacheco, J.; Wimmer-Schweingruber, R. F. +10 more
Aims: We perform a statistical study of the relations between the properties of solar energetic electron (SEE) events measured by the MESSENGER mission from 2010 to 2015 and the parameters of the respective parent solar activity phenomena in order to identify the potential correlations between them. During the time of analysis, the MESSENGER …
VLBI imaging of high-redshift galaxies and protoclusters at low radio frequencies with the International LOFAR Telescope
van Weeren, R. J.; Röttgering, H. J. A.; Miley, G. K. +4 more
It is generally known that luminous, ultra-steep spectrum radio sources are preferentially associated with massive galaxies at high redshifts. In this paper, we describe a pilot project directed at such objects to demonstrate the feasibility and importance of using the LOw-Frequency ARray (LOFAR) data to study the most distant massive galaxies und…
Verification of Gaia Data Release 3 Single-lined Spectroscopic Binary Solutions With Three Transiting Low-mass Secondaries
Bieryla, Allyson; Latham, David W.; Quinn, Samuel N. +18 more
While secondary mass inferences based on single-lined spectroscopic binary (SB1) solutions are subject to $\sin i$ degeneracies, this degeneracy can be lifted through the observations of eclipses. We combine the subset of Gaia Data Release 3 SB1 solutions consistent with brown dwarf-mass secondaries with the Transiting Exoplanet Survey Satellite (…
Investigating Whistler-Mode Wave Intensity Along Field Lines Using Electron Precipitation Measurements
Zhang, Xiao-Jia; Angelopoulos, Vassilis; Tsai, Ethan +1 more
Electron fluxes in Earth's radiation belts are significantly affected by their resonant interaction with whistler-mode waves. This wave-particle interaction often occurs via first cyclotron resonance and, when intense and nonlinear, can accelerate subrelativistic electrons to relativistic energies while also scattering them into the atmospheric lo…
Discovery and Timing of Millisecond Pulsars with the Arecibo 327 MHz Drift-scan Survey
Freire, Paulo C. C.; Deneva, Julia S.; McLaughlin, Maura A. +6 more
We present the discovery and timing solutions of four millisecond pulsars (MSPs) discovered in the Arecibo 327 MHz Drift-Scan Pulsar Survey. Three of these pulsars are in binary systems, consisting of a redback (PSR J2055+1545), a black widow (PSR J1630+3550), and a neutron star-white dwarf binary (PSR J2116+1345). The fourth MSP, PSR J2212+2450, …