Search Publications
Is There an Enormous Cold Front at the Virial Radius of the Perseus Cluster?
Fabian, A. C.; Sanders, J. S.; Walker, S. A. +3 more
We present new XMM-Newton observations extending the mosaic of the Perseus cluster out to the virial radius to the west. Previous studies with ROSAT have reported a large excess in surface brightness to the west, possibly the result of large-scale gas sloshing. In our new XMM-Newton observations we have found two X-ray surface brightness edges at …
Discovery of hot subdwarfs covered with helium-burning ash
Werner, Klaus; Reindl, Nicole; Geier, Stephan +1 more
Helium-rich subdwarf O stars (sdOs) are hot compact stars in a pre-white dwarf evolutionary state. Most of them have effective temperatures and surface gravities in the range Teff = 40 000-50 000 K and log g = 5.5-6.0. Their atmospheres are helium dominated. If present at all, C, N, and O are trace elements. The abundance patterns are e…
Kinematics of the molecular interstellar medium probed by Gaia: steep velocity dispersion-size relation, isotropic turbulence, and location-dependent energy dissipation
Li, Guang-Xing; Chen, Bing-Qiu; Zhou, Ji-Xuan
The evolution of the molecular interstellar medium is controlled by processes such as turbulence, gravity, stellar feedback, and Galactic shear. AL a part of the ISM-6D project, using Gaia astrometric measurements towards a sample of young stellar objects (YSOs), we study the morphology and kinematic structure of the associated molecular gas. We i…
Primordial black hole dark matter in the context of extra dimensions
Vincent, Aaron C.; Song, Ningqiang; Friedlander, Avi +2 more
Theories of large extra dimensions (LEDs) such as the Arkani-Hamed, Dimopoulos and Dvali scenario predict a "true" Planck scale M⋆ near the TeV scale, while the observed Mp l is due to the geometric effect of compact extra dimensions. These theories allow for the creation of primordial black holes (PBHs) in the early Universe…
Magnetosheath Jet Occurrence Rate in Relation to CMEs and SIRs
Geyer, Paul; Temmer, Manuela; Plaschke, Ferdinand +6 more
Magnetosheath jets constitute a significant coupling effect between the solar wind (SW) and the magnetosphere of the Earth. In order to investigate the effects and forecasting of these jets, we present the first-ever statistical study of the jet production during large-scale SW structures like coronal mass ejections (CMEs), stream interaction regi…
Late-onset Circumstellar Medium Interactions are Rare: An Unbiased GALEX View of Type Ia Supernovae
Shappee, Benjamin J.; Anand, Gagandeep S.; Tucker, Michael A. +2 more
Using ultraviolet (UV) light curves, we constrain the circumstellar environments of 1080 Type Ia supernovae (SNe Ia) within z < 0.5 from archival Galaxy Evolution Explorer (GALEX) observations. All SNe Ia are required to have pre- and post-explosion GALEX observations to ensure adequate subtraction of the host-galaxy flux. Using the late-time G…
Conditions for Direct Black Hole Seed Collapse near a Radio-loud Quasar 1 Gyr after the Big Bang
Overzier, Roderik A.
Observations of luminous quasars and their supermassive black holes at z ≳ 6 suggest that they formed at dense matter peaks in the early universe. However, few studies have found definitive evidence that the quasars lie at cosmic density peaks, in clear contrast with theory predictions. Here we present new evidence that the radio-loud quasar SDSS …
High-frequency Magnetic Fluctuations in Space Plasmas and the Role of Electron Landau Damping
Telloni, Daniele; Vecchio, Antonio; Lepreti, Fabio +1 more
While low-frequency plasma fluctuations in the interplanetary space have been successfully described in the framework of classical turbulence, high-frequency fluctuations still represent a challenge for theoretical models. At these scales, kinetic plasma processes are at work, but although some of them have been identified in spacecraft measuremen…
Multimessenger Constraints on Magnetic Fields in Merging Black Hole-Neutron Star Binaries
Haiman, Zoltán; D'Orazio, Daniel J.; Vigna-Gómez, Alejandro +2 more
The LIGO-Virgo-KAGRA Collaboration recently detected gravitational waves (GWs) from the merger of black hole-neutron star (BHNS) binary systems GW200105 and GW200115. No coincident electromagnetic (EM) counterparts were detected. While the mass ratio and BH spin in both systems were not sufficient to tidally disrupt the NS outside the BH event hor…
Metallicity Distribution Function of the Eridanus II Ultra-faint Dwarf Galaxy from Hubble Space Telescope Narrowband Imaging
Dolphin, Andrew E.; Martin, Nicolas; Starkenburg, Else +9 more
We use deep narrowband CaHK (F395N) imaging taken with the Hubble Space Telescope (HST) to construct the metallicity distribution function (MDF) of Local Group ultra-faint dwarf galaxy Eridanus II (Eri II). When combined with archival F475W and F814W data, we measure metallicities for 60 resolved red giant branch stars as faint as m F475W