Search Publications
Magnetosphere-Ionosphere Drivers of Transient-Large-Amplitude Geomagnetic Disturbances: Statistical Analysis and Event Study
Nishimura, Yukitoshi; Moldwin, Mark B.; Weygand, James M. +2 more
We present a comprehensive statistical analysis of high-frequency transient-large-amplitude (TLA) magnetic perturbation events that occurred at 12 high-latitude ground magnetometer stations throughout Solar Cycle 24 from 2009 to 2019. TLA signatures are defined as one or more second-timescale dB/dt interval with magnitude ≥6 nT/s within an hour ev…
Fabry-Pérot etalons in solar astronomy. A review
del Toro Iniesta, J. C.; Orozco Suárez, D.; Bailén, F. J.
During the last decades, the use of Fabry-Pérot etalons as filtergraphs has become frequent in solar instruments. The main reason is that they stand out for offering quasi-monochromatic, two-dimensional fields of view much higher than those provided by conventional slit-based spectrographs in a given time interval. Unfortunately, they also present…
Dissecting Earth's Magnetosphere: 3D Energy Transport in a Simulation of a Real Storm Event
Toth, G.; Pulkkinen, T. I.; Brenner, A. +1 more
We present new analysis methods of 3D MHD output data from the Space Weather Modeling Framework during a simulated storm event. Earth's magnetosphere is identified in the simulation domain and divided based on magnetic topology and the bounding magnetopause definition. Volume energy contents and surface energy fluxes are analyzed for each subregio…
A reduction procedure and pipeline for the detection of trans-Neptunian objects using occultations
Ofek, Eran O.; Nir, Guy; Zackay, Barak
Kuiper belt objects smaller than a few kilometres are difficult to observe directly. They can be detected when they randomly occult a background star. Close to the ecliptic plane, each star is occulted once every tens of thousands of hours, and occultations typically last for less than a second. We present an algorithm, and companion pipeline, for…
The galaxy counterpart and environment of the dusty damped Lyman-α absorber at z = 2.226 towards Q 1218+0832
Östlin, G.; Milvang-Jensen, B.; Fynbo, J. P. U. +8 more
We report on further observations of the field of the quasar Q 1218+0832. Geier et al. (2019, A&A, 625, L9) presented the discovery of the quasar resulting from a search for quasars reddened and dimmed by dust in foreground damped Lyman-α absorbers (DLAs). The DLA is remarkable by having a very large H I column density close to 1022…
Confirmation of Color-dependent Centroid Shift Measured After 1.8 Years with HST
Lu, Jessica R.; Cole, Andrew A.; Fukui, Akihiko +10 more
We measured the precise masses of the host and planet in the OGLE-2003-BLG-235 system, when the lens and source were resolving, with 2018 Keck high resolution images. This measurement is in agreement with the observation taken in 2005 with the Hubble Space Telescope (HST). In the 2005 data, the lens and sources were not resolved and the measuremen…
Centre-to-limb variations in coronal hole and quiet sun regions obtained with IRIS spectroscopic observations
Young, Peter R.; Kayshap, Pradeep
The centre-to-limb variations (CLV) of Gaussian fit parameters of the transition region Si IV 1402.77 Å spectral line in quiet Sun (QS) and coronal hole (CH) regions are presented. The results are derived from a full-disc mosaic scan obtained by the Interface Region Imaging Spectrograph on 2017 September 24. The CLV for a CH transition region line…
Search for Planets in Hot Jupiter Systems with Multi-Sector TESS Photometry. III. A Study of Ten Systems Enhanced with New Ground-Based Photometry
Amado, P. J.; Mugrauer, M.; Fernández, M. +12 more
The loneliness of hot Jupiters supports the high-eccentricity migration as a primary path leading to the formation of systems with those planets stripped of any close-in planetary companions. Here we present the null results of searches for low-mass planets close to hot Jupiters in 10 planetary systems: HAT-P-4, HAT-P-10, HAT-P-12, HAT-P-17, HAT-P…
Accretion-modified Stars in Accretion Disks of Active Galactic Nuclei: The Low-luminosity Cases and an Application to Sgr A*
Ho, Luis C.; Wang, Jian-Min; Li, Yan-Rong +3 more
In this paper, we investigate the astrophysical processes of stellar-mass black holes (sMBHs) embedded in advection-dominated accretion flows (ADAFs) of supermassive black holes (SMBHs) in low-luminosity active galactic nuclei. The sMBH is undergoing Bondi accretion at a rate lower than the SMBH. Outflows from the sMBH-ADAF dynamically interact wi…
The X-ray point source population hosted by globular clusters in the elliptical galaxy NGC 4261
Kundu, Arunav; Dage, Kristen C.; Zepf, Stephen E. +4 more
Utilizing archival Chandra X-ray Observatory data and Hubble Space Telescope globular cluster catalogues, we probe the time-domain properties of the low mass X-ray binary population in the elliptical galaxy NGC 4261. Of the 98 unique X-ray sources identified in this study, 62 sources are within the optical field of view and, of those, 33 per cent …