Search Publications
The CH radical at radio wavelengths: revisiting emission in the 3.3 GHz ground-state lines
Menten, Karl M.; Jacob, Arshia M.; Wiesemeyer, Helmut +1 more
Context. The intensities of the three widely observed radio-wavelength hyperfine structure (HFS) lines between the Λ-doublet components of the rotational ground state of CH are inconsistent with local thermodynamic equilibrium (LTE) and indicate ubiquitous population inversion. While this can be qualitatively understood assuming a pumping cycle th…
Multiwavelength Emission from Magnetically Arrested Disks around Isolated Black Holes
Kimura, Shigeo S.; Kashiyama, Kazumi; Hotokezaka, Kenta
We discuss the prospects for identifying the nearest isolated black holes (IBHs) in our Galaxy. IBHs accreting gas from the interstellar medium likely form magnetically arrested disks (MADs). We show that thermal electrons in the MADs emit optical signals through the thermal synchrotron process while nonthermal electrons accelerated via magnetic r…
The Mie representation for Mercury's magnetic field
Glassmeier, K. -H.; Narita, Y.; Motschmann, U. +4 more
The parameterization of the magnetospheric field contribution, generated by currents flowing in the magnetosphere is of major importance for the analysis of Mercury's internal magnetic field. Using a combination of the Gauss and the Mie representation (toroidal–poloidal decomposition) for the parameterization of the magnetic field enables the anal…
Integrated Photometry of Multiple Stellar Populations in Globular Clusters
Milone, A. P.; Cordoni, G.; Marino, A. F. +8 more
Evidence that multiple populations (MPs) are common properties of globular clusters (GCs) has accumulated over the past decades from clusters in the Milky Way and in its satellites. This finding has revived research into GCs, and suggested that their formation at high redshift must have been a much more complex phenomenon than imagined before. How…
Exploring the Stellar Rotation of Early-type Stars in the LAMOST Medium-resolution Survey. II. Statistics
Deng, Licai; de Grijs, Richard; Sun, Weijia +1 more
Angular momentum is a key property regulating star formation and evolution. However, the physics driving the distribution of the stellar rotation rates of early-type main-sequence stars is as yet poorly understood. Using our catalog of 40,034 early-type stars with homogeneous $v\sin i$ parameters, we review the statistical properties of their stel…
Estimating [α/Fe] from Gaia low-resolution BP/RP spectra using the ExtraTrees algorithm
Fouesneau, Morgan; Andrae, René; Korn, Andreas J. +2 more
Context. Gaia Data Release 3 will contain more than a billion sources with positions, parallaxes, and proper motions. In addition, for hundreds of millions of stars, it will include low-resolution blue photometer (BP) and red photometer (RP) spectra. Obtained by dispersing light with prisms, these spectra have resolutions that are too low to allow…
Direct Imaging of Exoplanets beyond the Radial Velocity Limit: Application to the HD 134987 System
Gonzalez-Quiles, Junellie; Kane, Stephen R.; Girard, Julien H. +4 more
Future direct imaging missions will primarily observe planets that have been previously detected, mostly via the radial velocity (RV) technique, to characterize planetary atmospheres. In the meantime, direct imaging may discover new planets within existing planetary systems that have bright enough reflected flux but insufficient signals for other …
Ion bulk speeds and temperatures in the diamagnetic cavity of comet 67P from RPC-ICA measurements
Nilsson, Hans; Stenberg Wieser, Gabriella; Wieser, Martin +6 more
Comets are constantly interacting with the solar wind. When the comet activity is high enough, this leads to the creation of a magnetic field free region around the nucleus known as the diamagnetic cavity. It has been suggested that the ion-neutral drag force is balancing the magnetic pressure at the cavity boundary, but after the visit of Rosetta…
Proper motion measurements for stars up to 100 kpc with Subaru HSC and SDSS Stripe 82
Wang, Wenting; Komiyama, Yutaka; Takada, Masahiro +6 more
We present proper motion measurements for more than 0.55 million main-sequence stars, by comparing astrometric positions of matched stars between the multiband imaging data sets from the Hyper Suprime-Cam (HSC) Survey and the Sloan Digital Sky Survey (SDSS) Stripe 82. In doing this, we use 3 million galaxies to recalibrate the astrometry and set u…
Automated Detection of Accelerating Solar Eruptions Using Parabolic Hough Transform
West, Matthew J.; Mierla, Marilena; Pant, Vaibhav +3 more
Solar eruptions such as coronal mass ejections (CMEs) observed in the inner solar corona (up to 4 R⊙) show acceleration profiles that appear as parabolic ridges in height-time plots. Inspired by the white-light automated detection algorithms Computer Aided CME Tracking System (CACTus) and Solar Eruptive Events Detection System (SEEDS), …