Search Publications
Reconstructing the XUV Spectra of Active Sun-like Stars Using Solar Scaling Relations with Magnetic Flux
Notsu, Yuta; Namekata, Kosuke; Toriumi, Shin +3 more
The Kepler space telescope and Transiting Exoplanet Survey Satellite unveiled that Sun-like stars frequently host exoplanets. These exoplanets are subject to fluxes of ionizing radiation in the form of X-ray and extreme-ultraviolet (EUV) radiation that may cause changes in their atmospheric dynamics and chemistry. While X-ray fluxes can be observe…
A Highly Magnified Gravitationally Lensed Red QSO at z = 2.5 with a Significant Flux Ratio Anomaly
Djorgovski, S. G.; Stern, Daniel; Lacy, Mark +12 more
We present the discovery of a gravitationally lensed dust-reddened QSO at z = 2.517, identified in a survey for QSOs by infrared selection. Hubble Space Telescope imaging reveals a quadruply lensed system in a cusp configuration, with a maximum image separation of ~1.″8. We find that, compared to the central image of the cusp, the neighboring brig…
Evidence of a Massive Stellar Disruption in the X-Ray Spectrum of ASASSN-14li
Ramirez-Ruiz, Enrico; Drake, Jeremy J.; Raymond, John +7 more
The proximity and duration of the tidal disruption event ASASSN-14li led to the discovery of narrow, blueshifted absorption lines in X-rays and UV. The gas seen in X-ray absorption is consistent with bound material close to the apocenter of elliptical orbital paths, or with a disk wind similar to those seen in Seyfert-1 active galactic nuclei. We …
SRGeJ045359.9+622444: A 55 Minute Period Eclipsing AM Canum Venaticorum Star Discovered from a Joint SRG/eROSITA + ZTF Search
Szkody, Paula; El-Badry, Kareem; Graham, Matthew J. +24 more
AM Canum Venaticorum (AM CVn) systems are ultracompact binaries where a white dwarf accretes from a helium-rich degenerate or semidegenerate donor. Some AM CVn systems will be among the loudest sources of gravitational waves for the upcoming Laser Interferometer Space Antenna; yet the formation channel of AM CVns remains uncertain. We report the s…
Are JWST/NIRCam Color Gradients in the Lensed z = 2.3 Dusty Star-forming Galaxy El Anzuelo Due to Central Dust Attenuation or Inside-out Galaxy Growth?
Grogin, Norman A.; Koekemoer, Anton M.; Pirzkal, Nor +25 more
Gradients in the mass-to-light ratio of distant galaxies impede our ability to characterize their size and compactness. The long-wavelength filters of JWST's NIRCam offer a significant step forward. For galaxies at Cosmic Noon (z ~ 2), this regime corresponds to the rest-frame near-infrared, which is less biased toward young stars and captures emi…
Investigating the M GCS-M h Relation in the Most Massive Galaxies
Harris, William E.; Dornan, Veronika
The relation between the total mass contained in the globular clusters of a galaxy and the mass of its dark-matter halo has been found observationally to be nearly linear over five decades of mass. However, the high-mass end of this relation is not well determined from previous data and shows large scatter. We analyze the globular cluster systems …
WIYN Open Cluster Study. LXXXVII. Hubble Space Telescope Ultraviolet Detection of Hot White Dwarf Companions to Blue Lurkers in M67
Mathieu, Robert D.; Nine, Andrew C.; Gosnell, Natalie M. +1 more
We present the results of our Hubble Space Telescope far-ultraviolet survey of the blue lurkers (BLs) in M67. We find evidence for two white dwarf (WD) companions among the BLs that are indicative of mass transfer from an evolved companion, one in WOCS 14020 and the other in WOCS 3001. The cooling ages of the WDs suggest that mass transfer in thes…
A Single Ejection Model of the DART/Dimorphos Debris Trail
Jewitt, David; Kim, Yoonyoung
The collision of the NASA DART spacecraft with asteroid Dimorphos resulted in the formation of a distinctive and long-lived debris trail, formed by the action of solar radiation pressure on ejected particles. This trail briefly displayed a double appearance, which has been interpreted as the result of a double ejection. We present a model that can…
IXPE and XMM-Newton Observations of the Soft Gamma Repeater SGR 1806-20
Kaaret, Philip; Wu, Kinwah; Enoto, Teruaki +96 more
Recent observations with the Imaging X-ray Polarimetry Explorer (IXPE) of two anomalous X-ray pulsars provided evidence that X-ray emission from magnetar sources is strongly polarized. Here we report on the joint IXPE and XMM-Newton observations of the soft γ-repeater SGR 1806-20. The spectral and timing properties of SGR 1806-20 derived from XMM-…
Revisiting the Properties of X-Ray Active Galactic Nuclei in the SSA22 Protocluster: Normal Supermassive Black Hole and Host-galaxy Growth for AGNs in a z = 3.09 Overdensity
Kubo, Mariko; Umehata, Hideki; Alexander, David M. +6 more
We analyze the physical properties of eight X-ray-selected active galactic nuclei (AGNs) and one candidate protoquasar system (ADF22A1) in the z = 3.09 SSA22 protocluster by fitting their X-ray-to-IR spectral energy distributions (SEDs) using our SED-fitting code, LIGHTNING (https://www.github.com/rafaeleufrasio/lightning). We recover star formati…