Search Publications
Constraining Atmospheric Composition from the Outflow: Helium Observations Reveal the Fundamental Properties of Two Planets Straddling the Radius Gap
Knutson, Heather A.; Horne, Keith; Collins, Karen A. +13 more
TOI-836 is a ∼2–3 Gyr K dwarf with an inner super Earth (R = 1.7 R⊕, P = 3.8 days) and an outer mini-Neptune (R = 2.6 R⊕, P = 8.6 days). JWST/NIRSpec 2.8–5.2 µm transmission spectra are flat for both planets. We present Keck/NIRSPEC observations of escaping helium for super-Earth b, which shows no excess absorption in t…
Unfolding X-Ray Spectral Data: Conditions and Applications
Huenemoerder, David P.; Gunderson, Sean J.
We present conditions for which X-ray spectra can be "unfolded" to present an accurate representation of the true source spectra. The method we use to unfold the data is implemented in the Interactive Spectral Interpretation Software and distinguishes itself as being model-independent. We find that this method of unfolding makes accurate represent…
Characterizing Superflares in HR 1099 Using Temporal and Spectral Analysis of XMM-Newton Observations
Srivastava, A. K.; Pandey, Jeewan C.; Didel, Shweta
In the present paper, we analyze three energetic X-ray flares from the active RS CVn binary HR 1099 using data obtained from XMM-Newton. The flare duration ranges from 2.8 to 4.1 hr, with e-folding rise and decay times in the range of 27–38 minutes and 1.3–2.4 hr, respectively, indicating rapid rise and slower decay phases. The flare frequency for…
Long-term X-Ray Variability on the Benchmark YSO HL Tau
Schneider, P. C.; Kastner, Joel H.; Principe, David A. +4 more
HL Tau is one of the most well-studied Class I young stellar objects (YSOs), including frequent observations at near- and mid-infrared, (sub)millimeter, and X-ray wavelengths. We present the results of an X-ray variability monitoring campaign with XMM-Newton in 2020 and X-ray grating spectroscopy from Chandra/HETGS in 2018. We find that the X-ray …
AstroSat/UVIT Far- and Near-UV Deep Field Around IC 4329A
Dewangan, Gulab C.; Ganguly, Piyali; Rani, Priyanka
We present high-resolution near-ultraviolet (NUV) and far-ultraviolet (FUV) deep imaging of the field around the Seyfert galaxy IC 4329A based on five observations performed with the Ultra-Violet Imaging Telescope (UVIT) onboard AstroSat. The long exposures of 82.9 ks in the NUV (N245M; λmean = 2447 Å; Δλ = 270 Å) and 92.2 ks in the FUV…
Elemental Abundances in the Diffuse Interstellar Medium from Joint Far-ultraviolet and X-Ray Spectroscopy: Iron, Oxygen, Carbon, and Sulfur
Costantini, E.; Mehdipour, M.; García, J. A. +10 more
In this study, we investigate interstellar absorption lines along the line of sight toward the galactic low-mass X-ray binary Cygnus X-2. We combine absorption line data obtained from high-resolution X-ray spectra collected with the Chandra and XMM-Newton satellites, along with far-UV absorption lines observed by the Hubble Space Telescope's (HST)…
Firmamento: A Multimessenger Astronomy Tool for Citizen and Professional Scientists
Giommi, Paolo; Doro, Michele; Pollock, A. M. T. +12 more
Firmamento (https://firmamento.hosting.nyu.edu) is a new-concept, web-based, and mobile-friendly data analysis tool dedicated to multifrequency/multimessenger emitters, as exemplified by blazars. Although initially intended to support a citizen researcher project at New York University–Abu Dhabi, Firmamento has evolved to be a valuable tool for pr…
Fast and Robust Noise Background Modeling and Quasiperiodic Oscillation Detection for Astronomical Time Series
Xu, Chang
Spectrum with confidence levels is a commonly used method for quasiperiodic oscillation (QPO) detection, but it is prone to yield false positives for two reasons: poor choice and/or biased modeling of the null hypothesis (or noise background). Motivated by this, we propose a new time-domain maximum-likelihood estimation method, which can quickly a…
Extinction of Taurus, Orion, Perseus and California Molecular Clouds Based on the LAMOST, 2MASS, and Gaia Surveys. II. The Extinction Law
Wang, Shu; Jiang, Biwei; Li, Jun +1 more
The extinction law from ultraviolet (UV) to infrared (IR; 0.2–24 µm) is determined by relying on the blue-edge method and color-excess ratios for some nearby molecular clouds, from the low-mass star-forming region to the massive star-forming region. The observational data are collected from nine photometric surveys, along with stellar parame…
Demography of Stellar Radio Population within 500 pc: A VLASS-Gaia DR3 Study
Narang, Mayank; Tyagi, H.; Shridharan, B. +5 more
In this work, we have carried out a systematic analysis of the Very Large Array Sky Survey (VLASS) quick look catalogs together with Gaia DR3 to identify the optical counterparts of 3 GHz radio emitters within 500 pc to obtain a homogeneous statistical sample of stellar radio sources. We have identified distinct populations of 3 GHz emitters acros…