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Observational Studies on the Near-infrared Unidentified Emission Bands in Galactic H II Regions
Onaka, Takashi; Sakon, Itsuki; Shimonishi, Takashi +4 more
Using a large collection of near-infrared spectra (2.5-5.4 µm) of Galactic H II regions and H II region-like objects, we perform a systematic investigation of astronomical polycyclic aromatic hydrocarbon (PAH) features. Thirty-six objects were observed using the infrared camera on board the AKARI satellite as a part of a director's time prog…
Herschel Planetary Nebula Survey (HerPlaNS). First detection of OH+ in planetary nebulae
Sahai, R.; Izumiura, H.; Kastner, J. H. +15 more
Aims: We report the first detections of OH+ emission in planetary nebulae (PNe).
Methods: As part of an imaging and spectroscopy survey of 11 PNe in the far-IR using the PACS and SPIRE instruments aboard the Herschel Space Observatory, we performed a line survey in these PNe over the entire spectral range between 51µm an…
The Spatially Resolved Bipolar Nebula of Sakurai's Object
Hinkle, Kenneth H.; Joyce, Richard R.
Sakurai's object (V4334 Sgr), the final flash object discovered in the mid-1990s, underwent rapid cooling during the first decade of the 21st century becoming as faint as K ~ 25. This stage of evolution has ceased. Between observations in 2010 September and 2013 April V4334 Sgr brightened >2 mag to K = 14.2 and the effective temperature increas…
Areas of Polar Coronal Holes from 1996 Through 2010
Karna, N.; Hess Webber, S. A.; Pesnell, W. D. +1 more
Polar coronal holes (PCHs) trace the magnetic variability of the Sun throughout the solar cycle. Their size and evolution have been studied as proxies for the global magnetic field. We present measurements of the PCH areas from 1996 through 2010, derived from an updated perimeter-tracing method and two synoptic-map methods. The perimeter-tracing m…
Radio-Optical Reference Frame Link Using the U.S. Naval Observatory Astrograph and Deep CCD Imaging
Zacharias, N.; Zacharias, M. I.
Between 1997 and 2004 several observing runs were conducted, mainly with the CTIO 0.9 m, to image International Celestial Reference Frame (ICRF) counterparts (mostly QSOs) in order to determine accurate optical positions. Contemporary to these deep CCD images, the same fields were observed with the U.S. Naval Observatory astrograph in the same ban…
Close Companions to Two High-redshift Quasars
Strauss, Michael A.; Fan, Xiaohui; Jiang, Linhua +5 more
We report the serendipitous discoveries of companion galaxies to two high-redshift quasars. SDSS J025617.7+001904 is a z = 4.79 quasar included in our recent survey of faint quasars in the SDSS Stripe 82 region. The initial MMT slit spectroscopy shows excess Lyα emission extending well beyond the quasar's light profile. Further imaging and spectro…
Single field inflation with modulated potential in light of Planck and BICEP2
Wan, Youping; Li, Siyu; Li, Mingzhe +3 more
The recently released BICEP2 data detected the primordial B-mode polarization in the cosmic microwave background (CMB) map which strongly supports for a large tensor-to-scalar ratio, and, thus, is found to be in tension with the Planck experiment with no evidence of primordial gravitational waves. Such an observational tension, if confirmed by for…
Signatures of the non-Maxwellian κ-distributions in optically thin line spectra. I. Theory and synthetic Fe IX-XIII spectra
Mason, H. E.; Del Zanna, G.; Dzifčáková, E. +1 more
Aims: We investigate the possibility of diagnosing the degree of departure from the Maxwellian distribution using single-ion spectra originating in astrophysical plasmas in collisional ionization equilibrium.
Methods: New atomic data for excitation of Fe ix - Fe xiii are integrated under the assumption of a κ-distribution of electron ene…
Not-so-simple Stellar Populations in the Intermediate-age Large Magellanic Cloud Star Clusters NGC 1831 and NGC 1868
Deng, Licai; de Grijs, Richard; Li, Chengyuan
Using a combination of high-resolution Hubble Space Telescope/Wide-Field and Planetary Camera-2 observations, we explore the physical properties of the stellar populations in two intermediate-age star clusters, NGC 1831 and NGC 1868, in the Large Magellanic Cloud based on their color-magnitude diagrams. We show that both clusters exhibit extended …
High-resolution Submillimeter and Near-infrared Studies of the Transition Disk around Sz 91
Henning, Thomas; Terada, Hiroshi; Usuda, Tomonori +55 more
To reveal the structures of a transition disk around a young stellar object in Lupus, Sz 91 , we have performed aperture synthesis 345 GHz continuum and CO(3-2) observations with the Submillimeter Array (~1''-3'' resolution) and high-resolution imaging of polarized intensity at the Ks -band using the HiCIAO instrument on the Subaru Tele…