Zobrazeno 1 - 10
of 32
pro vyhledávání: '"J. S. Ulvestad"'
Publikováno v:
Proceedings of the International Astronomical Union. 2004:61-64
We present Chandra observations of the nuclear region of nearby inactive galaxies. The sample is selected based on the absence or weakness of optical emission lines in the nucleus. X-ray nuclei are detected in four out of six galaxies. This result, a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::0068f890329e6cd9cb81301a6b02c86b
https://doi.org/10.1017/s1743921304001462
https://doi.org/10.1017/s1743921304001462
Autor:
Karl M. Menten, Moshe Elitzur, Alison B. Peck, Heino Falcke, Andreas Brunthaler, Carsten Henkel, Jack F. Gallimore, J. S. Ulvestad
Publikováno v:
The Astrophysical Journal. 590:149-161
We report on single-dish monitoring and extremely high angular resolution observations of the flaring H2O megamaser in the Seyfert 2 galaxy Mrk 348. The H2O line is redshifted by ~130 km/s with respect to the systemic velocity, is very broad, with a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7f1bed225a14ea4801f5c98c8a414608
https://doi.org/10.1086/374924
https://doi.org/10.1086/374924
Publikováno v:
Black Holes in Binaries and Galactic Nuclei: Diagnostics, Demography and Formation ISBN: 3540415815
We have surveyed two large samples of nearby low-luminosity AGN with the VLA to search for flat-spectrum radio cores, similar to Sgr A* in the Galactic Center. Roughly one third of all galaxies are detected (roughly one half if HII transition objects
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::e6decf5ca1e1e238f068feef254fc774
https://doi.org/10.1007/10720995_45
https://doi.org/10.1007/10720995_45
Autor:
Alan L. Roy, Andrew S. Wilson, Heino Falcke, Thomas P. Krichbaum, J. M. Wrobel, J. S. Ulvestad
The Very Long Baseline Array has been used at 15 GHz to image the milliarcsecond structure of the Seyfert galaxies Mrk 231 and Mrk 348 at two epochs separated by about 1.7 yr. Both galaxies contain parsec-scale double radio sources whose components h
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::03b7da3ac8edaef7558f847ad3d9b3fb
Autor:
J. E. Pringle, J. S. Ulvestad, Anne L. Kinney, Cathie J. Clarke, Robert Antonucci, Henrique R. Schmitt
We demonstrate that, by combining optical, radio and X-ray observations of a Seyfert, it is possible to provide a direct measurement of the angle $\beta$ between the direction of the radio jet and the normal to the plane of the spiral host galaxy. To
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4c03ff7952ead474027ad33b24ebd484
Autor:
Arpad Szomoru, Leonid Gurvits, R. T. Schilizzi, Jonathan D. Romney, Hideyuki Kobayashi, Richard W. Porcas, Robert A. Preston, Masato Tsuboi, Simon T. Garrington, Alan R. Whitney, David L. Jauncey, Xiaoyu Hong, Christopher John Salter, J. S. Ulvestad
Publikováno v:
Proceedings of the International Astronomical Union. 4:342-343
This triennium began with an action to re-create the Terms of Reference for the Working Group Global VLBI (WG-GV). These had been lost over the years since the Group was established in 1990. Fortunately, the personal archive of one long-term member y
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::551d4990dd3f77caf05fd01d371592dc
https://doi.org/10.1017/s1743921308025817
https://doi.org/10.1017/s1743921308025817
Publikováno v:
Springer Proceedings in Physics ISBN: 9783642623486
We report new observations of the H2O megamaser in the Seyfert 2 galaxy Mrk 348. The line is redshifted by ∼130 km s-1 with respect to the systemic velocity, is extremely broad, with a FWHM of 130 km s-1, and has no detectable high velocity compone
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::8fca7a4b9e42748a89263488e761c338
https://doi.org/10.1007/978-3-642-18902-9_30
https://doi.org/10.1007/978-3-642-18902-9_30
Publikováno v:
International Astronomical Union Colloquium. 164:199-200
The Seyfert 1/starburst/IR galaxy Mrk 231 (UGC 08058), at z = 0.0422, has been imaged with the VLBA at frequencies ranging from 1.4 GHz to 22 GHz. The radio image shows a triple source of total size 50 mas (30h−1 pc), with a self-absorbed central c
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::81e14e11bcd8e54fe73a3baf12b706e3
https://doi.org/10.1017/s025292110004519x
https://doi.org/10.1017/s025292110004519x
Publikováno v:
International Astronomical Union Colloquium. 164:301-302
We are surveying eight nearby Seyfert galaxies (four Sy1s and four Sy2s) that have compact radio cores, using the VLBA. We are interested in parsec-scale morphology and low-frequency absorption effects, and so are observing four frequencies (1.6, 4.8
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::ad7782338477f01491954252d80a2184
https://doi.org/10.1017/s0252921100045668
https://doi.org/10.1017/s0252921100045668
Autor:
J. S. Ulvestad, R. P. Linfield
Publikováno v:
International Astronomical Union Colloquium. 164:397-398
We are developing a future space VLBI mission, ARISE, that would involve placing a VLBA-equivalent radio telescope in a highly elliptical Earth orbit. The telescope would operate at VLBI frequencies of 5, 22, 43, and 86 GHz, as well as being capable
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::966b3afc1b8b683a6de744821b3136e7
https://doi.org/10.1017/s025292110004611x
https://doi.org/10.1017/s025292110004611x