Search Publications
Organic matter in space: from star dust to the Solar System
Kwok, Sun
Organic compounds of high degree of complexity are now known to be widespread in the Universe, ranging from objects in our Solar System to distant galaxies. Through the techniques of millimeter-wave spectroscopy, over 140 molecules have been identified through their rotational transitions. Space infrared spectroscopy has detected the stretching an…
On properties of narrow CMEs observed with SOHO/LASCO
Mittal, Nishant; Narain, Udit; Pandey, Kumud +1 more
We have investigated properties such as speed, angular width, location, acceleration and occurrence rate of narrow CMEs (defined as having angular width ≤20°) observed during 1996–2007 by SOHO/LASCO. The results obtained are compared with those of normal CMEs (angular width >20°) from the same time interval to find whether there are any real di…
Optical and UV monitor (OM) on-board XMM-Newton
Talavera, Antonio; OMCal Team
The Optical and UV Monitor (OM), is a small telescope co-aligned with the main XMM-Newton X-ray telescopes. It can perform imaging with six broad band lenticular filters covering the range 180 nm to 600 nm. In addition, two grisms allow the user to obtain low resolution spectra in the same range. The detector is an intensified CCD. The instrument …
Initial mass function biases created by binning and unresolved systems
Maíz Apellániz, Jesús
I discuss two of the possible sources of biases in the determination of the stellar initial mass function: binning and the existence of unresolved components. The first source is important for clusters with a small number of stars detected in a given mass bin, while the second is relevant for all clusters located beyond the immediate solar neighbo…
A Hubble Space Telescope/NICMOS view of the prototypical giant H ii region NGC604 in M33
Walborn, Nolan R.; Bolatto, Alberto; Barbá, Rodolfo H. +5 more
We present the first high-spatial-resolution near-infrared (NIR) imaging of NGC604, obtained with the NICMOS camera onboard the Hubble Space Telescope (HST). These NICMOS broad-band images reveal new NIR point sources, clusters, and diffuse structures. We find an excellent spatial correlation between the 8.4 GHz radio continuum and the 2.2 µ…
Very peculiar wind from BD+53°2790, the optical counterpart to 4U 2206+54
Negueruela, I.; Ribó, M.; Blay, P.
BD+53°2790, an O9.5V star, is the optical counterpart to the HMXRB 4U 2206+54. This system was classified initially as a BeX, but observational evidence soon stressed the need to revise this classification. The permanent asymmetry in the Hα line profiles (in contrast with the cyclic variations shown by Be stars), the variations in the profile of t…
Detecting metal-rich intermediate-age globular clusters in NGC4570 using K-band photometry
Kotulla, Ralf; Anders, Peter; Fritze, Uta
Globular cluster systems (GCSs) of most early-type galaxies feature two peaks in their optical colour distributions. Blue-peak globular clusters (GCs) are believed to be old and metal-poor, whereas the ages, metallicities, and the origin of the red-peak GCs are still being debated. We obtained deep K-band photometry and combined it with Hubble Spa…
The formation and evolution of massive stellar clusters in IC4662
Vacca, William D.; Gilbert, Andrea M.
We present a multiwavelength study of the formation of massive stellar clusters, their emergence from cocoons of gas and dust, and their feedback on surrounding matter. Using data that span from radio to optical wavelengths, including Spitzer and Hubble Space Telescope ACS observations, we examine the population of young star clusters in the centr…
Infrared spectral variations of three Mira variable carbon stars with the 11.3 µm SiC feature
Chen, Pei-Sheng; Shan, Hong-Guang; Yang, Xiao-Hong +1 more
The spectral variations of three Mira variable carbon stars, V CrB, T Dra and V Cyg in the infrared are investigated based on ISO SWS data. It is found that either continua or molecular/dust features were variable with time in the infrared for these carbon stars during one and a half year observations. When stars were brighter the infrared continu…
Probing young massive clusters with laser guide star adaptive optics
McCrady, Nate
We use laser guide star adaptive optics (LGS/AO) on the 10 m Keck II telescope to obtain high spatial resolution images of young massive clusters (YMCs) in NGC1569 and M82. These data probe YMC structure and the relation of the YMCs to the ambient field star population. The higher resolution of Keck LGS/AO relative to Hubble Space Telescope/NICMOS…