Search Publications
H2 Fluorescence in M Dwarf Systems: A Stellar Origin
Loyd, R. O. Parke; Roberge, Aki; Kruczek, Nicholas +7 more
Observations of molecular hydrogen (H2) fluorescence are a potentially useful tool for measuring the H2 abundance in exoplanet atmospheres. This emission was previously observed in {{M}} dwarfs with planetary systems. However, low signal-to-noise prevented a conclusive determination of its origin. Possible sources include exo…
Contribution of the first galaxies to the cosmic far-infrared/sub-millimeter background - I. Mean background level
De Rossi, María Emilia; Bromm, Volker
We study the contribution of the first galaxies to the far-infrared/sub-millimeter (FIR/sub-mm) extragalactic background light (EBL) by implementing an analytical model for dust emission. We explore different dust models, assuming different grain-size distributions and chemical compositions. According to our findings, observed reradiated emission …
Current sheets in comet 67P/Churyumov-Gerasimenko's coma
Coates, A. J.; Jones, G. H.; Glassmeier, K. -H. +16 more
The Rosetta Plasma Consortium (RPC) data are used to investigate the presence of current sheets in the coma of comet 67P/Churyumov-Gerasimenko. The interaction of the interplanetary magnetic field (IMF) transported by the solar wind toward the outgassing comet consists amongst others of mass loading and field line draping near the nucleus. The dra…
The Faintest WISE Debris Disks: Enhanced Methods for Detection and Verification
Metchev, Stanimir A.; Heinze, Aren; Patel, Rahul I. +1 more
In an earlier study, we reported nearly 100 previously unknown dusty debris disks around Hipparcos main-sequence stars within 75 pc by selecting stars with excesses in individual WISE colors. Here, we further scrutinize the Hipparcos 75 pc sample to (1) gain sensitivity to previously undetected, fainter mid-IR excesses and (2) remove spurious exce…
Multivariate statistical analysis of OSIRIS/Rosetta spectrophotometric data of comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lamy, P. L.; Lara, L. M. +42 more
Context. The ESA Rosetta mission explored comet 67P/Churyumov-Gerasimenko in 2014-2016, following its target before and after the perihelion passage on 13 August 2015. The NAC camera of the OSIRIS imaging system allowed to map the nucleus surface acquiring images with different filters in the visible wavelength range.
Aims: Here we study the …
Hot prominence detected in the core of a coronal mass ejection. II. Analysis of the C III line detected by SOHO/UVCS
Heinzel, P.; Anzer, U.; Jejčič, S. +3 more
Context. We study the physics of erupting prominences in the core of coronal mass ejections (CMEs) and present a continuation of a previous analysis.
Aims: We determine the kinetic temperature and microturbulent velocity of an erupting prominence embedded in the core of a CME that occurred on August 2, 2000 using the Ultraviolet Coronagraph a…
The cosmic microwave background Cold Spot anomaly: the impact of sky masking and the expected contribution from the integrated Sachs-Wolfe effect
Lahav, Ofer; Benoit-Lévy, Aurélien; Naidoo, Krishna
We re-analyse the cosmic microwave background (CMB) Cold Spot (CS) anomaly with particular focus on understanding the bias a mask (contaminated by Galactic and point sources) may introduce. We measure the coldest spot, found by applying the Spherical Mexican Hat Wavelet transform on 100 000 cut-sky (masked) and full-sky CMB simulated maps. The CS …
A mechanism for comet surface collapse as observed by Rosetta on 67P/Churyumov-Gerasimenko
Sierks, H.; Prialnik, D.
We explore a possible mechanism that may explain sudden depressions of surface areas on a comet nucleus, as suggested by observations of the Rosetta mission on comet 67P/Churyumov-Gerasimenko (hereafter, 67P/C-G). Assuming the area is covered by a thin, compact dust layer of low permeability to gas flow compared to deeper, porous layers, gas can a…
Energy-dependent variability of the bare Seyfert 1 galaxy Ark 120
Dewangan, Gulab C.; McHardy, I. M.; Mallick, Labani +1 more
We present results from a detailed spectral-timing analysis of a long ∼486 ks XMM-Newton observation of the bare Seyfert 1 galaxy Ark 120 which showed alternating diminution and increment in the 0.3-10 keV X-ray flux over four consecutive orbits in 2014. We study the energy-dependent variability of Ark 120 through broad-band X-ray spectroscopy, fr…
SOFIA-EXES Mid-IR Observations of [Fe II] Emission from the Extended Atmosphere of Betelgeuse
Ryde, N.; Greathouse, T. K.; Guinan, E. F. +5 more
We present a NASA-DLR SOFIA-Echelon Cross Echelle Spectrograph (EXES) and NASA Infrared Telescope Facility-Texas Echelon Cross Echelle Spectrograph (TEXES) mid-IR R≃ {{50,000}} spectral study of forbidden Fe II transitions in the early-type M supergiants, Betelgeuse (α Ori: M2 Iab) and Antares (α Sco: M1 Iab + B3 V). With EXES, we spectrally resol…