Search Publications
Baryonic Tully-Fisher relation for extremely low mass Galaxies
Sharina, M. E.; Begum, Ayesha; Chengalur, Jayaram N. +1 more
We study Tully-Fisher (TF) relations for a sample that combines extremely faint (MB < -14) galaxies along with bright (i.e. ~L*) galaxies. Accurate (~10 per cent) distances, I-band photometry and B - V colours are known for the majority of the galaxies in our sample. The faint galaxies are drawn from the Faint Irregular Ga…
Persistent Horizontal Flows and Magnetic Support of Vertical Threads in a Quiescent Prominence
Chae, Jongchul; Choe, G. S.; Lim, Eun-Kyung +2 more
There has been some controversy as to whether the magnetic fields of vertical threads seen in quiescent prominences are predominantly vertical or horizontal. We report finding special patterns of flow in a quiescent prominence observed by the Solar Optical Telescope aboard Hinode. This prominence is a small hedgerow prominence composed of many ver…
Initial Venus Express magnetic field observations of the Venus bow shock location at solar minimum
Barabash, S.; Russell, C. T.; Zhang, T. L. +10 more
In this study, magnetic field measurements obtained by the Venus Express spacecraft are used to determine the bow shock position at solar minimum. The best fit of bow shock location from solar zenith angle 20-120° gives a terminator bow shock location of 2.14 RV (1 RV=6052 km) which is 1600 km closer to Venus than the 2.40 R<…
The early expansion of cluster cores
Bastian, N.; Smith, L. J.; Goodwin, S. P. +4 more
The observed properties of young star clusters, such as the core radius and luminosity profile, change rapidly during the early evolution of the clusters. Here we present observations of six young clusters in M51 where we derive their sizes using Hubble Space Telescope (HST) imaging and ages using deep Gemini-North spectroscopy. We find evidence f…
Spectropolarimetric Observation of an Emerging Flux Region: Triggering Mechanisms of Ellerman Bombs
Shibata, K.; Ueno, S.; Kitai, R. +6 more
A high spatial resolution observation of an emerging flux region (EFR) was made using a vector magnetograph and a Hα Lyot filtergraph with the Domeless Solar Telescope at Hida Observatory on 2006 October 22. In Hα wing images, we could see many Ellerman bombs (EBs) in the EFR. Observations in two modes, slit scan and slit fixed, were performed wit…
The Stellar Mass Distribution in the Giant Star Forming Region NGC 346
Tosi, M.; Sabbi, E.; Nota, A. +8 more
Deep F555W and F814W Hubble Space Telescope (HST ) Advanced Camera for Survey (ACS) images are the basis for a study of the present-day mass function (PDMF) of NGC 346, the largest active star-forming region in the Small Magellanic Cloud (SMC). We find a PDMF slope of Γ = -1.43 ± 0.18 in the mass range 0.8-60 Msun, in excellent agreemen…
Molecular Gas in NUclei of GAlaxies (NUGA). IX. The decoupled bars and gas inflow in NGC 2782
Tacconi, L. J.; Hunt, L. K.; Krips, M. +8 more
We present CO(1-0) and CO(2-1) maps of the starburst/Seyfert 1 galaxy NGC 2782 obtained with the IRAM interferometer, at 2.1 arcsec×1.5 arcsec and 0.7 arcsec×0.6 arcsec resolution respectively. The CO emission is aligned along the stellar nuclear bar of radius ~1 kpc, configured in an elongated structure with two spiral arms at high pitch angle ~9…
Circumstellar water vapour in M-type AGB stars: radiative transfer models, abundances, and predictions for HIFI
Olofsson, H.; Schöier, F. L.; Bergman, P. +2 more
Context: Surprisingly high amounts of H2O have recently been reported in the circumstellar envelope around the M-type asymptotic giant branch star W Hya. This has lead to the speculation that evaporation of icy cometary or planetary bodies might be an effective ongoing mechanism in such systems. However, substantial uncertainties remain, as the re…
A microlensing study of the accretion disc in the quasar MG 0414+0534
Wyithe, J. S. B.; Bate, N. F.; Floyd, D. J. E. +1 more
Observations of gravitational microlensing in multiply imaged quasars currently provide the only direct probe of quasar emission region structure on submicroarcsecond scales. The analyses of microlensing variability are observationally expensive, requiring long-term monitoring of lensed systems. Here, we demonstrate a technique for constraining th…
Distribution and escape of molecular hydrogen in Titan's thermosphere and exosphere
Yelle, R. V.; Volk, K.; Cui, J.
We present an in-depth study of the distribution and escape of molecular hydrogen (H2) on Titan, based on the global average H2 distribution at altitudes between 1000 and 6000 km, extracted from a large sample of Cassini/Ion and Neutral Mass Spectrometer (INMS) measurements. Below Titan's exobase, the observed H2 d…