Search Publications
The Pristine survey - XV. A CFHT ESPaDOnS view on the Milky Way halo and disc populations
Jablonka, P.; Lardo, C.; Kordopatis, G. +14 more
We present a one-dimensional, local thermodynamic equilibrium homogeneous analysis of 132 stars observed at high resolution with ESPaDOnS. This represents the largest sample observed at high resolution (R ~ 40 000) from the Pristine survey. This sample is based on the first version of the Pristine catalogue and covers the full range of metalliciti…
Cross-checking SMBH mass estimates in NGC 6958 - I. Stellar dynamics from adaptive optics-assisted MUSE observations
Weilbacher, Peter M.; Krajnović, Davor; van de Ven, Glenn +9 more
Supermassive black hole masses (MBH) can dynamically be estimated with various methods and using different kinematic tracers. Different methods have only been cross-checked for a small number of galaxies and often show discrepancies. To understand these discrepancies, detailed cross-comparisons of additional galaxies are needed. We pres…
Magnetic helicity and energy of emerging solar active regions and their erruptivity
Liu, Y.; Nindos, A.; Liokati, E.
Aims: We investigate the role of the accumulation of magnetic helicity and magnetic energy in the generation of coronal mass ejections (CMEs) from emerging solar active regions (ARs).
Methods: Using vector magnetic field data obtained by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, we calculated the magne…
The TREX Survey: Kinematical Complexity Throughout M33's Stellar Disk and Evidence for a Stellar Halo
Williams, Benjamin F.; Gilbert, Karoline M.; Wojno, Jennifer +9 more
We present initial results from a large spectroscopic survey of stars throughout M33's stellar disk. We analyze a sample of 1667 red giant branch (RGB) stars extending to projected distances of ~11 kpc from M33's center (~18 kpc, or ~10 scale lengths, in the plane of the disk). The line-of-sight velocities of RGB stars show the presence of two kin…
Absolute Calibration of Cepheid Period-Luminosity Relations in NGC 4258
Casertano, Stefano; Filippenko, Alexei V.; Riess, Adam G. +6 more
Owing to its accurate distance measured from water-maser motions, NGC 4258 is one of the most important anchors for calibrating the Cepheid period-luminosity relations (PLRs). We expand on previous efforts and carry out a new Cepheid search in this system using the Hubble Space Telescope. We discover and measure a sample of 669 Cepheids in four ne…
Acceleration and cooling of the corona during X-ray flares from the Seyfert galaxy I Zw 1
Brandt, W. N.; Costantini, E.; Blandford, R. D. +2 more
We report on X-ray flares that were observed from the active galactic nucleus I Zwicky 1 (I Zw 1) in 2020 January by the NuSTAR and XMM-Newton observatories. The X-ray spectrum is well-described by a model comprised of the continuum emission from the corona and its reflection from the accretion disc around a rapidly spinning (a > 0.94) black ho…
Completeness of the Gaia verse - V. Astrometry and radial velocity sample selection functions in Gaia EDR3
Everall, Andrew; Boubert, Douglas
We risk reaching false scientific conclusions if we test our physical theories against subsets of the Gaia catalogue without correcting for the biased process by which stars make it into our sample. In this paper, we produce selection functions for three Gaia science samples to enable the community to correct for this bias. We estimate the probabi…
Geodesy of irregular small bodies via neural density fields
Izzo, Dario; Gómez, Pablo
Asteroids' and comets' geodesy is a challenging yet important task for planetary science and spacecraft operations, such as ESA's Hera mission tasked to look at the aftermath of the recent NASA DART spacecraft's impact on Dimorphos. Here we present a machine learning approach based on so-called geodesyNets which learns accurate density models of i…
Spirality: A Novel Way to Measure Spiral Arm Pitch Angle
Davis, Benjamin L.; Boe, Benjamin; Kennefick, Daniel +7 more
We present the MATLAB code Spirality, a novel method for measuring spiral arm pitch angles by fitting galaxy images to spiral templates of known pitch. Computation time is typically on the order of 2 min per galaxy, assuming 8 GB of working memory. We tested the code using 117 synthetic spiral images with known pitches, varying both the spiral pro…
Multi-spacecraft Observations of the Evolution of Interplanetary Coronal Mass Ejections between 0.3 and 2.2 au: Conjunctions with the Juno Spacecraft
Lugaz, Noé; Scolini, Camilla; Winslow, Réka M. +4 more
We present a catalog of 35 interplanetary coronal mass ejections (ICMEs) observed by the Juno spacecraft and at least one other spacecraft during its cruise phase to Jupiter. We identify events observed by MESSENGER, Venus Express, Wind, and STEREO with magnetic features that can be matched unambiguously with those observed by Juno. A multi-spacec…