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Probing the statistical properties of CMB B-mode polarization through Minkowski functionals
Wang, Kai; Santos, Larissa; Zhao, Wen
The detection of the magnetic type B-mode polarization is the main goal of future cosmic microwave background (CMB) experiments. In the standard model, the B-mode map is a strong non-gaussian field due to the CMB lensing component. Besides the two-point correlation function, the other statistics are also very important to dig the information of th…
High spatial resolution optical imaging of the multiple T Tauri system Lk Hα 262/Lk Hα 263
Rebolo, R.; Labadie, L.; Velasco, S. +12 more
We report high spatial resolution I' band imaging of the multiple T Tauri system LkHα 262/LkHα 263 obtained during the first commissioning period of the Adaptive Optics Lucky Imager (AOLI) at the 4.2-m William Herschel Telescope, using its Lucky Imaging mode. AOLI images have provided photometry for each of the two components LkHα 263 A and B (0.4…
Survival of Pure Disk Galaxies over the Last 8 Billion Years
Sachdeva, Sonali; Saha, Kanak
Pure disk galaxies without any bulge component, I.e., bulges that are neither classical nor pseudo, seem to have escaped the effects of merger activity that are inherent to hierarchical galaxy formation models as well as strong internal secular evolution. We discover that a significant fraction (∼15%-18%) of disk galaxies in the Hubble Deep Field …
AKARI/IRC Near-infrared Spectral Atlas of Galactic Planetary Nebulae
Onaka, Takashi; Matsuura, Mikako; Sakon, Itsuki +2 more
Near-infrared (2.5-5.0 µm) low-resolution (λ/Δλ ∼ 100) spectra of 72 Galactic planetary nebulae (PNe) were obtained with the Infrared Camera (IRC) in the post-helium phase. The IRC, equipped with a 1‧ × 1‧ window for spectroscopy of a point source, was capable of obtaining near-infrared spectra in a slit-less mode without any flux loss due t…
Characterisation of red supergiants in the Gaia spectral range
Negueruela, Ignacio; González-Fernández, Carlos; Dorda, Ricardo
Context. The infrared calcium triplet and its nearby spectral region have been used for spectral and luminosity classification of late-type stars, but the samples of cool supergiants (CSGs) used have been very limited (in size, metallicity range, and spectral types covered). The spectral range of the Gaia Radial Velocity Spectrograph (RVS) covers …
Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids
Schaefer, Gail H.; Bond, Howard E.; Evans, Nancy Remage +4 more
We have conducted an imaging survey with the Hubble Space Telescope Wide Field Camera 3 (WFC3) of 70 Galactic Cepheids, typically within 1 kpc, with the aim of finding resolved physical companions. The WFC3 field typically covers the 0.1 pc area where companions are expected. In this paper, we identify 39 Cepheids having candidate companions, base…
Suprathermal Electrons at Saturn's Bow Shock
Coates, A. J.; Dougherty, M. K.; Fujimoto, M. +4 more
The leading explanation for the origin of galactic cosmic rays is particle acceleration at the shocks surrounding young supernova remnants (SNRs), although crucial aspects of the acceleration process are unclear. The similar collisionless plasma shocks frequently encountered by spacecraft in the solar wind are generally far weaker (lower Mach numb…
Deep Herschel PACS point spread functions
Abergel, A.; Bianchi, S.; Bocchio, M.
The knowledge of the point spread function (PSF) of imaging instruments represents a fundamental requirement for astronomical observations. The Herschel PACS PSFs delivered by the instrument control centre are obtained from observations of the Vesta asteroid, which provides a characterisation of the central part and, therefore, excludes fainter fe…
Scaling laws of coronal loops compared to a 3D MHD model of an active region
Peter, H.; Bingert, S.; Bourdin, Ph. -A.
Context. The structure and heating of coronal loops have been investigated for decades. Established scaling laws relate fundamental quantities like the loop apex temperature, pressure, length, and coronal heating.
Aims: We test these scaling laws against a large-scale 3D magneto-hydrodynamics (MHD) model of the solar corona, which became feas…
Collisional excitation of doubly and triply deuterated ammonia ND2H and ND3 by H2
Roueff, E.; Lis, D. C.; Daniel, F. +6 more
The availability of collisional rate coefficients is a prerequisite for an accurate interpretation of astrophysical observations, since the observed media often harbour densities where molecules are populated under non-local thermodynamic equilibrium conditions. In the current study, we present calculations of rate coefficients suitable to describ…