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Ionic loss from Venus upper ionosphere via plasma wake
Moslem, W. M.; Elsheikh, I. A.; Tolba, R. E. +2 more
Recent observations have detected significant escape of ions from the Venusian ionosphere. The measurements indicate that the composition of the escaping mix of ions may reach a critical ratio of H+ : O+ ≈ 2 : 1 , suggesting that it originated in water molecules, in line with the observed dryness of the planet. In this work, …
Limits to Ionization-parameter Mapping as a Diagnostic of HII Region Optical Depth
Oey, M. S.; Sawant, Amit N.; Micheva, Genoveva +2 more
We employ ionization-parameter mapping (IPM) to infer the optical depth of H II regions in the northern half of M33. We construct [O III]λ5007/[O II]λ3727 and [O III]λ5007/[S II]λ6724 ratio maps from narrowband images continuum-subtracted in this way, from which we classify the H II regions by optical depth to ionizing radiation, based on their io…
The ionization fraction in OMC-2 and OMC-3
Menten, K. M.; Tielens, A. G. G. M.; Wyrowski, F. +4 more
Context. The electron density (ne−) plays an important role in setting the chemistry and physics of the interstellar medium. However, measurements of ne− in neutral clouds have been directly obtained only toward a few lines of sight or they rely on indirect determinations.
Aims: We use carbon radio …
X-Rays in Cepheids: XMM-Newton Observations of η Aql
Mérand, Antoine; Drake, Jeremy J.; Guzik, Joyce A. +13 more
X-ray bursts have recently been discovered in the Cepheids δ Cep and β Dor modulated by the pulsation cycle. We have obtained an observation of the Cepheid η Aql with the XMM-Newton satellite at the phase of maximum radius; the phase at which there is a burst of X-rays in δ Cep. No X-rays were seen from the Cepheid η Aql at this phase, and the imp…
Pair lines of sight observations of multiphase gas bearing O VI in a galaxy environment
Beckett, Alexander; Morris, Simon L.; Muzahid, Sowgat +2 more
Using HST/COS spectra of the twin quasar lines of sight Q 0107-025A & Q 0107-025B, we report on the physical properties, chemical abundances, and transverse sizes of a multiphase medium in a galaxy field at z = 0.399. The angular separation between the quasars corresponds to a physical separation of 520 kpc at the absorber redshift. The absorb…
Stereoscopic measurements of coronal Doppler velocities
Barczynski, K.; Mierla, M.; Berghmans, D. +8 more
Context. The Solar Orbiter mission, with an orbit outside the Sun-Earth line and leaving the ecliptic plane, opens up opportunities for the combined analysis of measurements obtained by solar imagers and spectrometers. For the first time different space spectrometers will be located at wide angles to each other, allowing three-dimensional (3D) spe…
GTC/CanariCam Deep Mid-infrared Imaging Survey of Northern Stars within 5 pc
Rebolo, Rafael; Caballero, José A.; Pinfield, David J. +7 more
In this work we present the results of a direct imaging survey for brown dwarf companions around the nearest stars at the mid-infrared 10 micron range (λ c = 8.7 µm, Δλ = 1.1 µm) using the CanariCam instrument on the 10.4 m Gran Telescopio Canarias (GTC). We imaged the 25 nearest stellar systems within 5 pc of the Sun at d…
An XMM-Newton catalogue of BL Lacs
Racero, E.; Álvarez Crespo, N.; de la Calle Pérez, I. +1 more
Aims: We present an XMM-Newton catalogue of BL Lac X-ray, optical, and UV properties based on cross-correlation with the 1151 BL Lacs listed in the fifth edition of the Roma-BZCAT.
Methods: We searched for the X-ray counterparts to these objects in the field of view of all pointed observations in the XMM-Newton archive over nearly 20 yea…
Blueshifted Hydrogen Emission and Shock Wave of RR Lyrae Variables in SDSS and LAMOST
Deng, Licai; Liu, Chao; Zhang, Huawei +4 more
Hydrogen emissions of RR Lyrae variables are the imprints of shock waves traveling through their atmospheres. We develop a pattern recognition algorithm, which is then applied to single-epoch spectra of the Sloan Digital Sky Survey and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey. These two spectroscopic surveys covered ~10…
Spectral study of V565 Mon: probable FU Ori-like or chemically peculiar star
Andreasyan, Hasmik
We present a detailed spectroscopic study of pre-main sequence star V565 Mon, which is the illuminating star of the Parsamian 17 cometary nebula. Observations were performed with the 2.6 m telescope in Byurakan Astrophysical Observatory on 2018 February 15. Radial velocities and equivalent widths of the most prominent lines of V565 Mon are present…