Search Publications
CMB anomalies and the effects of local features of the inflaton potential
Gariazzo, Stefano; Cadavid, Alexander Gallego; Romano, Antonio Enea
Recent analysis of the WMAP and Planck data have shown the presence of a dip and a bump in the spectrum of primordial perturbations at the scales
An Active Galactic Nucleus Caught in the Act of Turning Off and On
Greene, Jenny E.; Stern, Daniel; Comerford, Julia M. +5 more
We present the discovery of an active galactic nucleus (AGN) that is turning off and then on again in the z = 0.06 galaxy SDSS J1354+1327. This episodic nuclear activity is the result of discrete accretion events that could have been triggered by a past interaction with the companion galaxy that is currently located 12.5 kpc away. We originally ta…
Are Internetwork Magnetic Fields in the Solar Photosphere Horizontal or Vertical?
Lites, B. W.; Borrero, J. M.; Danilovic, S. +1 more
Using many observations obtained during 2007 with the Spectro-Polarimeter of the Hinode Solar Optical Telescope, we explore the angular distribution of magnetic fields in the quiet internetwork regions of the solar photosphere. Our work follows from the insight of Stenflo, who examined only linear polarization signals in photospheric lines, thereb…
KELT-18b: Puffy Planet, Hot Host, Probably Perturbed
Bieryla, Allyson; Latham, David W.; Berlind, Perry +54 more
We report the discovery of KELT-18b, a transiting hot Jupiter in a 2.87-day orbit around the bright (V = 10.1), hot, F4V star BD+60 1538 (TYC 3865-1173-1). We present follow-up photometry, spectroscopy, and adaptive optics imaging that allow a detailed characterization of the system. Our preferred model fits yield a host stellar temperature of 667…
Mars Under Primordial Solar Wind Conditions: Mars Express Observations of the Strongest CME Detected at Mars Under Solar Cycle #24 and its Impact on Atmospheric Ion Escape
Barabash, Stas; Nilsson, Hans; Holmström, Mats +3 more
An extremely strong Coronal Mass Ejection (CME) impacted Mars on 12 July 2011, while the Mars Express spacecraft was present inside the nightside ionosphere. Estimated solar wind density and speed during the event are 39 particles cm-3 and 730 km/s, corresponding to nominal solar wind flux at Mars when the solar system was ∼1.1 Ga old. …
X-ray flaring in PDS 456 observed in a high-flux state
Turner, T. J.; Reeves, J. N.; Braito, V. +3 more
We present an analysis of a 190 ks (net exposure) Suzaku observation, carried out in 2007, of the nearby (z = 0.184) luminous (Lbol ∼ 1047 erg s-1) quasar PDS 456. In this observation, the intrinsically steep bare continuum is revealed compared to subsequent observations, carried out in 2011 and 2013, where the sou…
HADES RV Programme with HARPS-N at TNG. VI. GJ 3942 b behind dominant activity signals
Rebolo, R.; Ribas, I.; Morales, J. C. +29 more
Context. Short- to mid-term magnetic phenomena on the stellar surface of M-type stars can resemble the effects of planets in radial velocity data, and may also hide them.
Aims: We analyze 145 spectroscopic HARPS-N observations of GJ 3942 taken over the past five years and additional photometry in order to disentangle stellar activity effects …
XMM-Newton observation of MV Lyr and the sandwiched model confirmation
Ness, J. -U.; Dobrotka, A.; Nucita, A. A. +1 more
We present spectral and timing analyses of simultaneous X-ray and UV observations of the VY Scl system MV Lyr taken by XMM-Newton, containing the longest continuous X-ray + UV light curve and highest signal-to-noise X-ray (EPIC) spectrum to date. The RGS spectrum displays emission lines plus continuum, confirming model approaches to be based on th…
HD 164492C: a rapidly rotating, Hα-bright, magnetic early B star associated with a 12.5 d spectroscopic binary
Rivinius, Th.; Wade, G. A.; Alecian, E. +6 more
We employ high-resolution spectroscopy and spectropolarimetry to derive the physical properties and magnetic characteristics of the multiple system HD 164492C, located in the young open cluster M20. The spectrum reveals evidence of three components: a broad-lined early B star (HD 164492C1), a narrow-lined early B star (HD 164492C2) and a late B st…
D/H Ratios on Saturn and Jupiter from Cassini CIRS
Fletcher, L. N.; Lellouch, E.; Irwin, P. G. J. +7 more
We present new measurements of the deuterium abundance on Jupiter and Saturn, showing evidence that Saturn's atmosphere contains less deuterium than Jupiter's. We analyzed far-infrared spectra from the Cassini Composite Infrared Spectrometer to measure the abundance of HD on both giant planets. Our estimate of the Jovian D/H = (2.95 ± 0.55) × 10