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Time variations of narrow absorption lines in high resolution quasar spectra
York, D. G.; Péroux, C.; Bergeron, J. +2 more
Aims: We have searched for temporal variations of narrow absorption lines in high resolution quasar spectra. A sample of five distant sources were assembled, for which two spectra are available, either VLT/UVES or Keck/HIRES, which were taken several years apart.
Methods: We first investigate under which conditions variations in absorpti…
Ubiquitous time variability of integrated stellar populations
van Dokkum, Pieter G.; Choi, Jieun; Conroy, Charlie
Long-period variable stars arise in the final stages of the asymptotic giant branch phase of stellar evolution. They have periods of up to about 1,000 days and amplitudes that can exceed a factor of three in the I-band flux. These stars pulsate predominantly in their fundamental mode, which is a function of mass and radius, and so the pulsation pe…
Effects of Saturn's magnetospheric dynamics on Titan's ionosphere
Gurnett, D. A.; Jackman, C. M.; Kurth, W. S. +9 more
We use the Cassini Radio and Plasma Wave Science/Langmuir probe measurements of the electron density from the first 110 flybys of Titan to study how Saturn's magnetosphere influences Titan's ionosphere. The data is first corrected for biased sampling due to varying solar zenith angle and solar energy flux (solar cycle effects). We then present res…
Linearized iterative least-squares (LIL): a parameter-fitting algorithm for component separation in multifrequency cosmic microwave background experiments such as Planck
Khatri, Rishi
We present an efficient algorithm for least-squares parameter fitting, optimized for component separation in multifrequency cosmic microwave background (CMB) experiments. We sidestep some of the problems associated with non-linear optimization by taking advantage of the quasi-linear nature of the foreground model. We demonstrate our algorithm, lin…
Error analysis for retrieval of Venus' IR surface emissivity from VIRTIS/VEX measurements
Haus, Rainer; Kappel, David; Arnold, Gabriele
Venus' surface emissivity data in the infrared can serve to explore the planet's geology. The only global data with high spectral, spatial, and temporal resolution and coverage at present is supplied by nightside emission measurements acquired by the Visible and InfraRed Thermal Imaging Spectrometer VIRTIS-M-IR (1.0 - 5.1 µm) aboard ESA's Ve…
Host Galaxy Properties and Black Hole Mass of Swift J164449.3+573451 from Multi-wavelength Long-term Monitoring and HST Data
Urata, Yuji; Sakamoto, Takanori; Im, Myungshin +6 more
We study the host galaxy properties of the tidal disruption object Swift J164449.3+573451 using long-term optical to near-infrared (NIR) data. First, we decompose the galaxy surface brightness distribution and analyze the morphology of the host galaxy using high-resolution Hubble Space Telescope WFC3 images. We conclude that the host galaxy is bul…
Physical properties of the extreme Centaur and super-comet candidate 2013 AZ60
Pál, A.; Szabó, Gy. M.; Acosta-Pulido, J. +12 more
We present estimates of the basic physical properties including size and albedo of the extreme Centaur 2013 AZ60. These properties have been derived from optical and thermal infrared measurements. Our optical measurements revealed a probable full period of ≈9.4 h with a shallow amplitude of 4.5%. By combining optical brightness informat…
XMM-Newton observation of SNR J0533-7202 in the Large Magellanic Cloud
Haberl, F.; Filipović, M. D.; Maggi, P. +5 more
Aims: We present an X-ray study of the supernova remnant SNR J0533-7202 in the Large Magellanic Cloud (LMC) and determine its physical characteristics based on its X-ray emission.
Methods: We observed SNR J0533-7202 with XMM-Newton (background flare-filtered exposure times of 18 ks EPIC-pn and 31 ks EPIC-MOS1, EPIC-MOS2). We produced X-r…
An empirical approach to modeling ion production rates in Titan's ionosphere II: Ion production rates on the nightside
Coates, A. J.; Rymer, A.; Wellbrock, A. +9 more
Ionization of neutrals by precipitating electrons and ions is the main source of Titan's nightside ionosphere. This paper has two goals: (1) characterization of the role of electron impact ionization on the nightside ionosphere for different magnetospheric conditions and (2) presentation of empirical ion production rates determined using densities…
RATAN-600 Observations of Small-Scale Structures with High Spectral Resolution
Alissandrakis, C. E.; Bogod, V. M.; Kaltman, T. I. +1 more
We present observations of quiet-Sun small-scale structures (SSS) in the microwave range with the Radio Astronomical Telescope of the Academy of Sciences 600 (RATAN-600) spectral-polarization facility in a wide range of frequencies. The SSS are regularly recorded in routine observations of the large reflector-type radio telescope and represent man…