Search Publications

First Detection of HCO⁺ Absorption in the Magellanic System

Murray, Claire E.; Stanimirović, Snežana; Wong, Tony +9 more

We present the first detection of HCO⁺ absorption in the Magellanic System. Using the ATCA, we observed nine extragalactic radio continuum sources behind the Magellanic System and detected HCO⁺ absorption toward one source located behind the leading edge of the Magellanic Bridge. The detection is located at an LSR velocity of…

Origin of the Diffuse, Far Ultraviolet Emission in the Interarm Regions of M101

Calzetti, Daniela; Leitherer, Claus; Chandar, Rupali +4 more

We present images from the Solar Blind Channel on the Hubble Space Telescope that resolve hundreds of far-ultraviolet (FUV) emitting stars in two ∼1 kpc² interarm regions of the grand-design spiral M101. The luminosity functions of these stars are compared with predicted distributions from simple star formation histories, and are best r…

Chemical abundances in the PN Wray16-423 in the Sagittarius dwarf spheroidal galaxy: constraining the dust composition

Otsuka, Masaaki

We performed a detailed analysis of elemental abundances, dust features, and polycyclic aromatic hydrocarbons (PAHs) in the C-rich planetary nebula (PN) Wray16-423 in the Sagittarius dwarf spheroidal galaxy, based on a unique data set taken from the Subaru/HDS, MPG/ESO FEROS, HST/WFPC2, and Spitzer/IRS. We performed the first measurements of Kr, F…

HerMES: disentangling active galactic nuclei and star formation in the radio source population

Hatziminaoglou, E.; Bock, J.; Cooray, A. +12 more

We separate the extragalactic radio source population above ∼50 µJy into active galactic nuclei (AGN) and star-forming sources. The primary method of our approach is to fit the infrared spectral energy distributions (SEDs), constructed using Spitzer/IRAC (Infrared Array Camera) and Multiband Imaging Photometer for Spitzer (MIPS) and Herschel…

Investigation of the Chirikov resonance overlap criteria for equatorial magnetosonic waves

Walker, S. N.; Canu, P.; Balikhin, M. A. +2 more

Observations of equatorial magnetosonic waves made during the Cluster Inner Magnetospheric Campaign clearly show discrete spectra consisting of emissions around harmonics of the proton gyrofrequency. Equatorial magnetosonic waves are important because of their ability to efficiently scatter electrons in energy and pitch angle. This wave-particle i…

Observations of water with Herschel/HIFI toward the high-mass protostar AFGL 2591

van Dishoeck, E. F.; van der Tak, F. F. S.; Wyrowski, F. +2 more

Context. Water is an important chemical species in the process of star formation, and a sensitive tracer of physical conditions in star-forming regions because of its rich line spectrum and large abundance variations between hot and cold regions.
Aims: We use spectrally resolved observations of rotational lines of H₂O and its isoto…

VLT FORS2 optical imaging and spectroscopy of nine luminous type 2 AGN at 0.3 < z < 0.6 - I. Ionized gas nebulae

Humphrey, A.; Villar-Martín, M.; Arribas, S. +4 more

We present optical imaging and long slit spectroscopic observations of nine luminous type 2 active galactic nuclei (AGN) within the redshift range 0.3 < z < 0.6 based on Very Large Telescope Focal Reducer and Low Dispersion Spectrograph (VLT FORS2) data. Most objects (6/9) are high luminosity Seyfert 2, and three are type 2 quasars (QSO2), w…

Interdependencies Between the Actively Controlled Cluster Spacecraft Potential, Ambient Plasma, and Electric Field Measurements

Nakamura, Rumi; Torkar, Klaus; Andriopoulou, Maria

Star-forming regions at the periphery of the supershell surrounding the Cyg OB1 association - I. The star cluster vdB 130 and its ambient gas and dust medium

Wiebe, D. S.; Moiseev, A. V.; Rastorguev, A. S. +6 more

Stellar population and the interstellar gas-dust medium in the vicinity of the open star cluster vdB 130 are analysed using optical observations taken with the 6 m telescope of the Special Astrophysical Observatory of Russian Academy of Sciences and the 125 cm telescope of the Sternberg Astronomical Institute, Lomonosov Moscow State University alo…

Probing the nature of the pre-merging system Hickson Compact Group 31 through integral field unit data^★

Mendes de Oliveira, C.; de Mello, D. F.; Amram, P. +3 more

We present a study of the kinematics and the physical properties of the central region of the Hickson Compact Group 31 (HCG 31), focusing on the HCG 31A+C system, using integral field spectroscopy data taken with the Gemini South Telescope. The main players in the merging event (galaxies A and C) are two dwarf galaxies, which have had one close en…