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Related papers: VLA HI Zeeman Observations Toward the W49 Complex

200 papers

We have carried out a multi-species study of a region which has had previous measurements of strong magnetic fields through the CN Zeeman effect in order to to explore the relationship between CN and N$_2$H$^+$, both of which have evidence…

Solar and Stellar Astrophysics · Physics 2012-09-03 Nicholas S. Hakobian , Richard M. Crutcher

Using HIPASS data, we have searched for HI in a ~25x25 sq.deg. region centred on the Fornax cluster. Within a velocity search range of 300 - 3700 km/s and a lower flux limit of ~40 mJy, 110 galaxies with HI emission were detected, one of…

With IRAM-30m/HERA, we have detected CO(2-1) gas complexes within 30 arcsec (~100 pc) from the center of M31 amounting to a minimum total mass of 4.2 x 10^4 Msol (one third of the positions are detected). Averaging the whole HERA field, we…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 A. -L. Melchior , F. Combes

Arecibo mapping is reported of the neutral hydrogen distribution along selected directions out from the centers of two small High Velocity Clouds (HVC), W486 and W491. Both HVCs have a small inner region where the neutral hydrogen column…

Astrophysics · Physics 2009-11-07 G. L. Hoffman , E. E. Salpeter , M. G. Pocceschi

We present three epochs of VLBA observations of Galactic HI absorption toward the quasar 3C~138 with resolutions of 20 mas (~ 10 AU). This analysis includes VLBA data from observations in 1999 and 2002 along with a reexamination of 1995…

Astrophysics · Physics 2008-11-26 C. L. Brogan , B. A. Zauderer , T. J. Lazio , W. M. Goss , C. D. De Pree , M. D. Fasion

We present the results of HI 21-cm line observations to explore the nature of the high-velocity (HV) HI gas at l ~ 173{\circ} . In low-resolution Hi surveys this HV gas appears as faint, wing-like, HI emission that extends to velocities…

Astrophysics of Galaxies · Physics 2015-06-03 Ji-hyun Kang , Bon-Chul Koo , Chris Salter

Neutral Hydrogen (HI) provides a very important fuel for star formation, but is difficult to detect at high redshift due to weak emission, limited sensitivity of modern instruments, and terrestrial radio frequency interference (RFI) at low…

Astrophysics of Galaxies · Physics 2016-07-20 Lucas R. Hunt , D. J. Pisano , Stanislav S. Edel

Westerbork Radio Synthesis Telescope observation of the galaxy VV29=Arp188=UGC10214 shows that there are at least three distinct dynamical components whose kinematics can be traced in 21cm line emission. The system appears to be the result…

Astrophysics · Physics 2009-11-07 F. H. Briggs , O. Moller , J. L. Higdon , N. Trentham , E. Ramirez-Ruiz

We characterize the kinematic and magnetic properties of HI filaments located in a high Galactic latitude region ($165^\circ < \alpha < 195^\circ$ and $12^\circ < \delta < 24^\circ$). We extract three-dimensional filamentary structures…

Astrophysics of Galaxies · Physics 2023-09-20 Doyeon Avery Kim , Susan E Clark , Mary E Putman , Larry Li

The star formation rates in starburst galaxies are orders of magnitude higher than in local star-forming regions, and the origin of this difference is not well understood. We use sub-mm spectral line maps to characterize the physical…

Astrophysics of Galaxies · Physics 2015-06-04 Z. Nagy , F. F. S. van der Tak , G. A. Fuller , M. Spaans , R. Plume

We report on a study of the high-mass star formation in the the HII region W28A2 by investigating the molecular clouds extended over ~5-10 pc from the exciting stars using the 12CO and 13CO (J=1-0) and 12CO (J=2-1) data taken by the NANTEN2…

We have used the Westerbork array to carry out an unbiased wide-field survey for HI emission features, achieving an RMS sensitivity of about 18 mJy/Beam at a velocity resolution of 17 km/s over 1800 deg^2 and between -1000 < V_Hel<+6500…

Astrophysics · Physics 2016-08-30 Robert Braun , David Thilker , Rene Walterbos

We show 21-cm line profiles in the direction of stars and extragalactic objects, lying projected on high- and intermediate-velocity clouds (HVCs and IVCs). About half of these are from new data obtained with the Effelsberg 100-m telescope,…

Astrophysics · Physics 2009-11-06 B. P. Wakker , P. M. W. Kalberla , H. van Woerden , K. S. de Boer , M. E. Putman

The formation of high-mass stars is tightly linked to that of their parental clouds. We here focus on the high-density parts of W43, a molecular cloud undergoing an efficient event of formation. The cloud structure is studied with a column…

High velocity gas that does not conform to Galactic rotation is observed throughout the Galaxy's halo. One component of this gas, HI high velocity clouds (HVCs), have attracted attention since their discovery in the 1960s and remain…

Astrophysics of Galaxies · Physics 2017-08-24 Asger Grønnow , Thor Tepper-García , Joss Bland-Hawthorn , Naomi McClure-Griffiths

(Abridged) We present the results of a systematic GBT and GMRT survey for 21-cm absorption in a sample of 10 DLAs at 2<z_abs<3.4. Analysis of L-band VLBA images of the background QSOs are also presented. We detect 21-cm absorption in only…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 R. Srianand , N. Gupta , P. Petitjean , P. Noterdaeme , C. Ledoux , C. J. Salter , D. J. Saikia

We report on a second epoch of VLBA observations of the 1665 and 1667 MHz OH masers in the massive star-forming region W75 N. We find evidence to confirm the existence of very strong (~40 mG) magnetic fields near source VLA 2. The masers…

Astrophysics · Physics 2008-11-26 Vincent L. Fish , Mark J. Reid

Wisconsin H-Alpha Mapper (WHAM) observations reveal high-velocity and [NII]$\lambda6584$ emission lines in the same direction and velocity as ultraviolet absorption-line features that have been previously associated with the biconical…

Astrophysics of Galaxies · Physics 2020-08-19 Dhanesh Krishnarao , Robert A. Benjamin , L. Matthew Haffner

We report on the detection of low-column density neutral hydrogen clumps in the halo of the Milky Way. Using high-resolution (FWHM~7 km/s) optical spectra obtained with the VLT/UVES spectrograph we detect narrow interstellar absorption by…

Astrophysics · Physics 2009-11-11 Philipp Richter , Tobias Westmeier , Christian Bruens

To explore the origin of high-velocity gas in the direction of the Large Magellanic Cloud (LMC) we analyze absorption lines in the ultraviolet spectrum of a Galactic halo star that is located in front of the LMC at d=9.2 kpc distance. We…

Astrophysics of Galaxies · Physics 2015-11-18 P. Richter , K. S. de Boer , K. Werner , T. Rauch