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An ancient metal-poor population in M32, and halo satellite accretion in M31, identified by RR Lyrae stars
Lauer, Tod R.; Yang, S. -C.; Sarajedini, Ata +2 more
We present time series photometry of two fields near M32 using archival observations from the Advanced Camera for Surveys Wide Field Channel on-board the Hubble Space Telescope. One field is centred about 2 arcmin from M32, while the other is located 15 arcmin to the south-east of M31. The imaging covers a time baseline sufficient for the identifi…
Observational evidence for composite grains in an AGB outflow. MgS in the extreme carbon star LL Pegasi
Waters, L. B. F. M.; Mutschke, H.; de Koter, A. +5 more
The broad 30 µm feature in carbon stars is commonly attributed to MgS dust particles. However, reproducing the 30 µm feature with homogeneous MgS grains would require much more sulfur relative to the solar abundance. Direct gas-phase condensation of MgS occurs at a low efficiency. Precipitation of MgS on SiC precursor grains provides a…
XMM-Newton Observation of PSR B2224+65 and Its Jet
Cheng, K. S.; Takata, J.; Hui, C. Y. +4 more
We have investigated the pulsar PSR B2224+65 and its X-ray jet with XMM-Newton. Apart from the long X-ray jet which is almost perpendicular to the direction of proper motion, a putative extended feature at the pulsar position, which is oriented in the opposite direction to the proper motion, is also suggested by this deep X-ray imaging. Non-detect…
XMM-Newton evidence of shocked ISM in SN 1006: indications of hadronic acceleration
Miceli, M.; Bocchino, F.; Decourchelle, A. +5 more
Context. Shock fronts in young supernova remnants are the best candidates for being sites of cosmic ray acceleration up to a few PeV, though conclusive experimental evidence is still lacking.
Aims: Hadron acceleration is expected to increase the shock compression ratio, providing higher postshock densities, but X-ray emission from shocked amb…
Elusive Ethylene Detected in Saturn's Northern Storm Region
Fletcher, L. N.; Irwin, P. G. J.; Achterberg, R. K. +9 more
The massive eruption at 40°N (planetographic latitude) on Saturn in 2010 December has produced significant and lasting effects in the northern hemisphere on temperature and species abundances. The northern storm region was observed on many occasions in 2011 by Cassini's Composite Infrared Spectrometer (CIRS). In 2011 May, temperatures in the strat…
Herschel Far-infrared Photometric Monitoring of Protostars in the Orion Nebula Cluster
Billot, N.; Megeath, S. T.; Morales-Calderón, M. +2 more
We have obtained time series observations of the Orion Nebula Cluster at 70 µm and 160 µm from the Herschel/PACS Photometer. This represents the first wide-field far-infrared photometric monitoring of a young star-forming region. The acquired 35' × 35' maps show complex extended structures, with unprecedented detail, that trace the int…
Solar Rotation Effects on the Heliosheath Flow near Solar Minima
Pogorelov, Nikolai V.; Borovikov, Sergey N.; Ebert, Robert W.
The interaction between fast and slow solar wind (SW) due to the Sun's rotation creates corotating interaction regions (CIRs), which further interact with each other creating complex plasma structures at large heliospheric distances. We investigate the global influence of CIRs on the SW flow in the inner heliosheath between the heliospheric termin…
The 3.3 µm Polycyclic Aromatic Hydrocarbon Emission as a Star Formation Rate Indicator
Inami, Hanae; Nakagawa, Takao; Oyabu, Shinki +13 more
Polycyclic aromatic hydrocarbon (PAH) emission features dominate the mid-infrared spectra of star-forming galaxies and can be useful to calibrate star formation rates (SFRs) and diagnose ionized states of grains. However, the PAH 3.3 µm feature has not been studied as much as other PAH features since it is weaker than others and resides outs…
Disk-resolved photometry of Asteroid (2867) Steins
Jorda, L.; Lamy, P. L.; Keller, H. U. +2 more
We present a new method to perform disk-resolved photometry in order to investigate the intrinsic photometric properties of the surface of small Solar System bodies. We adopt the standard approach where a shape model is combined with a photometric formalism - in practise the Hapke formalism - to remove the effects of topography and recover the pho…
Inflow direction of interstellar neutrals deduced from pickup ion measurements at 1 AU
Galvin, Antoinette B.; Wimmer-Schweingruber, Robert F.; Bochsler, Peter +4 more
Observations of interstellar pickup ions inside the heliosphere provide an indirect method to access information on the surrounding interstellar medium. The so-called pickup ion focusing cone and pickup ion crescent, which show an imprint of the related longitudinal distribution of interstellar neutrals in form of two overabundances on the down- a…