ar X iv : a st ro - p h / 98 12 01 2 v 1 1 D ec 1 99 8 SUNSPOT TRANSITION REGION OSCILLATIONS IN NOAA 8156
نویسنده
چکیده
Based on observations obtained with the Solar and Heliospheric Observatory SOHO joint observing program for velocity fields in sunspot regions, we have detected 3 min transition region umbral oscillations in NOAA 8156. Simultaneous recordings of O V λ629 and N V λ1238, λ1242 with the SUMER instrument give the spatial distribution of power in the 3 min oscillations, both in intensity and line-of-sight velocity. Comparing loci with the same phase we find that the entire umbral transition region oscillates. The observed maxima in peak line intensity are nearly in phase with the maxima in velocity directed towards the observer. We discuss the suggestion that the waves are upward propagating acoustic waves. Subject headings: Sun: magnetic fields — Sun: oscillations — Sun: transition region — Sun: UV radiation — sunspots To appear in: Astrophysical Journal Letters
منابع مشابه
ar X iv : a st ro - p h / 98 12 12 1 v 1 7 D ec 1 99 8 Nuclear kpc - sized disks of spiral galaxies
A complex structure of nuclear disks of normal spiral galaxies is illustrated on the example of five galaxies, observed at 6m telescope. A problem of gravitational stability of nuclear disks is shortly discussed.
متن کاملar X iv : a st ro - p h / 98 12 35 8 v 1 1 8 D ec 1 99 8 RXTE OBSERVATIONS OF LMC X - 1
The luminous X-ray binary and black-hole candidate LMC X-1 has been observed with the Rossi X-ray Timing Explorer (RXT E) to search for quasi-periodic oscillations (QPO), previously reported in its high state. The source was observed monthly in a series of nine observations. Analysis of the temporal variations shows no evidence for QPO or other periodic changes, but correlations between the hig...
متن کاملar X iv : a st ro - p h / 98 12 32 8 v 1 1 7 D ec 1 99 8 MOND in the Early Universe
I explore some consequences of Milgrom’s modified dynamics for cosmology. There appear to be two promising tests for distinguishing MOND from CDM: (1) the rate of growth of structure and (2) the baryon fraction. These should be testable with observations of clusters at high redshift and the microwave background, respectively.
متن کاملar X iv : a st ro - p h / 98 12 04 3 v 1 2 D ec 1 99 8 What ’ s Emitting the Broad Emission Lines ?
I present a brief review about our ideas concerning the origin and nature of the broad line emitting gas. This is one of the outstanding problems in quasar research. I suggest the establishment of a central data base of high quality quasar spectra as a means to realize an understanding of quasars.
متن کاملar X iv : a st ro - p h / 01 12 42 3 v 1 1 8 D ec 2 00 1 The black hole mass of BL Lacs from stellar velocity dispersion of the host galaxy
The black hole mass of BL Lacs from stellar velocity dispersion of the host galaxy.
متن کامل