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A Deep Search for Five Molecules in the 49 Ceti Debris Disk
Hughes, A. Meredith; Roberge, Aki; Moór, Attila +9 more
Surprisingly strong CO emission has been observed from more than a dozen debris disks around nearby main-sequence stars. The origin of this CO is unclear, in particular whether it is left over from the protoplanetary disk phase or is second-generation material released from collisions between icy bodies like debris dust. The primary unexplored ave…
The IGRINS YSO Survey II: Veiling Spectra of Pre-main-sequence Stars in Taurus-Auriga
Tofflemire, Benjamin M.; López-Valdivia, Ricardo; Mace, Gregory +5 more
We present measurements of the H- and K-band veiling for 141 young stellar objects (YSOs) in the Taurus-Auriga star-forming region using high-resolution spectra from the Immersion Grating Near-Infrared Spectrometer. In addition to providing measurements of rH and rK, we produce low-resolution spectra of the excess emission ac…
Detection of coherent low-frequency radio bursts from weak-line T Tauri stars
Feeney-Johansson, A.; Purser, S. J. D.; Ray, T. P. +7 more
In recent years, thanks to new facilities such as LOFAR that are capable of sensitive observations, much work has been done on the detection of stellar radio emission at low frequencies. Such emission has commonly been shown to be coherent emission, generally attributed to electron-cyclotron maser (ECM) emission, and has usually been detected from…
Solar Soft X-ray Irradiance Variability, I: Segmentation of Hinode/XRT Full-Disk Images and Comparison with GOES (1 - 8 Å) X-Ray Flux
DeLuca, Edward; Weber, Mark; Adithya, H. N. +6 more
It is of great interest and importance to study the variabilities of solar EUV, UV and X-ray irradiance in heliophysics, in Earth's climate, and space weather applications. A careful study is required to identify, track, monitor and segment the different coronal features such as active regions (ARs), coronal holes (CHs), the background regions (BG…
First high-resolution optical spectra of the distant emission-line star VES 723 (IRAS 02110+6212)
Miroshnichenko, A. S.; Manset, N.; Klochkova, V. G. +3 more
The first high-resolution spectra (resolving powers of R ≥ 60 000) of the emission-line star VES 723, which has an unknown evolutionary status, were taken at the 6-m Big Telescope Alt-Azimuthal and the 3.6-m Canada-France-Hawaii Telescope. The spectrum is dominated with powerful emission lines of neutral hydrogen and helium, and forbidden singly i…
A puzzling non-detection of [O III] and [C II] from a z ≈ 7.7 galaxy observed with ALMA
Taniguchi, Y.; Umehata, H.; Zackrisson, E. +12 more
Context. Characterizing the galaxy population in the early Universe holds the key to understanding the evolution of these objects and the role they played in cosmic reionization. However, there have been very few observations at the very highest redshifts to date.
Aims: In order to shed light on the properties of galaxies in the high-redshift…
Probing the physical properties of the intergalactic medium using blazars
Morris, Simon L.; Fumagalli, Michele; Gatuzz, Efrain +1 more
We use Swift blazar spectra to estimate the key intergalactic medium (IGM) properties of hydrogen column density ($\mathit {N}\small {\rm HXIGM}$), metallicity, and temperature over a redshift range of 0.03 ≤ z ≤ 4.7, using a collisional ionization equilibrium model for the ionized plasma. We adopted a conservative approach to the blazar continuum…
The Y dwarf population with HST: unlocking the secrets of our coolest neighbours - I. Overview and first astrometric results
Bedin, L. R.; Fontanive, C.; Bardalez Gagliuffi, D. C.
In this paper, we present our project that aims at determining accurate distances and proper motions for the Y brown dwarf population using the Hubble Space Telescope. We validate the program with our first results, using a single new epoch of observations of the Y0pec dwarf WISE J163940.83-684738.6. These new data allowed us to refine its proper …
The effect of thermal conductivity on the outgassing and local gas dynamics from cometary nuclei
Thomas, N.; Marschall, R.; Gerig, S. -B. +3 more
Aims: The aim of this work is to investigate the parameters influencing the generation of the inner comae of a comet with a spherical nucleus and to model the gas activity distribution around its nuclei. Here, we investigate the influence of thermal conductivity combined with sub-surface H2O and CO2-ice sources on insola…
Primordial black hole origin for thermal gamma-ray bursts
Barco, Oscar
A binary black hole (BH) astrophysical scenario where a mass-constrained (2.5 × 10-13M⊙) primordial black hole (PBH) undergoes a radial fall on to its heavier component (such as a supermassive black hole, SMBH) is described as an intense gamma-ray emission event. As the relativistic PBH approaches the Schwarschild SMBH event …