Search Publications
The magnetic field of an isolated neutron star from X-ray cyclotron absorption lines
Caraveo, P. A.; Bignami, G. F.; Mereghetti, S. +1 more
Isolated neutron stars are highly magnetized, fast-rotating objects that form as an end point of stellar evolution. They are directly observable in X-ray emission, because of their high surface temperatures. Features in their X-ray spectra could in principle reveal the presence of atmospheres, or be used to estimate the strength of their magnetic …
Slow-mode standing waves observed by SUMER in hot coronal loops
Solanki, S. K.; Marsch, E.; Curdt, W. +2 more
We report the first detection of postflare loop oscillations seen in both Doppler shift and intensity. The observations were recorded in an Fe Xix line by the SUMER spectrometer on SOHO in the corona about 70 min after an M-class flare on the solar limb. The oscillation has a period of about 17 min in both the Doppler velocity and the intensity, b…
Dynamics of solar coronal loops. I. Condensation in cool loops and its effect on transition region lines
Peter, H.; Hansteen, V. H.; Müller, D. A. N.
We report numerical calculations of the condensation of plasma in short coronal loops, which have several interesting physical consequences. Firstly, we propose a connection between small, cool loops (T < 106 K), which constitute one of the basic components of the solar transition region, and prominences, in the sense that the same p…
The low-level radial velocity variability in Barnard's star (= GJ 699). Secular acceleration, indications for convective redshift, and planet mass limits
Kürster, M.; Hatzes, A. P.; Cochran, W. D. +6 more
We report results from 2 1/2 yr of high precision radial velocity (RV) monitoring of Barnard's star. The high RV measurement precision of the VLT-UT2+UVES of 2.65 m s-1 made the following findings possible. (1) The first detection of the change in the RV of a star caused by its space motion (RV secular acceleration). (2) An anti-correla…
A pulsational approach to near-infrared and visual magnitudes of RR Lyr stars
Degl'Innocenti, S.; Marconi, M.; Bono, G. +3 more
In this paper, we present an improved theoretical scenario concerning near-infrared and visual magnitudes of RR Lyr variables, as based on up-to-date pulsating models. New relations connecting V and K absolute magnitudes with periods, mass, luminosity and metal content are discussed separately for fundamental and first-overtone pulsators. We also …
Infrared Emission of Normal Galaxies from 2.5 to 12 Micron: Infrared Space Observatory Spectra, Near-Infrared Continuum, and Mid-Infrared Emission Features
Beichman, Charles A.; Dale, Daniel A.; Dinerstein, Harriet L. +6 more
We present ISOPHOT spectra of the regions 2.5-4.9 µm and 5.8-11.6 µm for a sample of 45 disk galaxies from the US Infrared Space Observatory Key Project on Normal Galaxies. The galaxies were selected to span the range in global properties of normal, star-forming disk galaxies in the local universe. The spectra can be decomposed into th…
Local galaxy flows within 5 Mpc
Sarajedini, A.; Dolphin, A. E.; Grebel, E. K. +8 more
We present Hubble Space Telescope/WFPC2 images of sixteen dwarf galaxies as part of our snapshot survey of nearby galaxy candidates. We derive their distances from the luminosity of the tip of the red giant branch stars with a typical accuracy of ~ 12%. The resulting distances are 4.26 Mpc (KKH 5), 4.74 Mpc (KK 16), 4.72 Mpc (KK 17), 4.66 Mpc (ESO…
Coronal Mass Ejections and Solar Polarity Reversal
Howard, R. A.; Gopalswamy, N.; Yashiro, S. +1 more
We report on a close relationship between the solar polarity reversal and the cessation of high-latitude coronal mass ejections (CMEs). This result holds good for individual poles of the Sun for cycles 21 and 23, for which CME data are available. The high-latitude CMEs provide a natural explanation for the disappearance of the polar crown filament…
Jupiter's main auroral oval observed with HST-STIS
Kim, J.; Clarke, J. T.; Cowley, S. W. H. +2 more
An extended series of FUV images obtained on 7 days during winter 2000-2001, with fixed pointing, yielded highly accurate tracking of emisson features as Jupiter rotated. They provided newly detailed measurements of the degree of corotation of auroral emissions and their variations with changing central meridian longitude. This 2-month data set pr…
The Fundamental Plane at z=1.27: First Calibration of the Mass Scale of Red Galaxies at Redshifts z>1
van Dokkum, Pieter G.; Stanford, S. A.
We present results on the fundamental plane of early-type galaxies in the cluster RDCS J0848+4453 at z=1.27. Internal velocity dispersions of three K-selected early-type galaxies are determined from deep Keck spectra, using absorption lines in the rest-frame wavelength range 3400-4000 Å. Structural parameters are determined from Hubble Space Teles…