共查询到20条相似文献，搜索用时 15 毫秒
1.
Osamu Kameya Tatsuhiko Hasegawa Naomi Hirano Munezo Seki Makoto Tosa Yoshiaki Taniguchi Keiya Takakubo 《Astrophysics and Space Science》1986,118(1-2):449-451
CS(J=1–0), C34S(J=1–0), and CH3OH(10–00A and E) emission lines in the core region of molecular cloud associated with NGC 7538 have been surveyed at angular resolution of 33. Distribution of CS column density shows two prominent peaks. Both blue and red wings in CS line are most prominent at 30 northwest of IRS 11.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.This work was carried out under the common use observation program at the Nobeyama Radio Observatory (NRO). NRO, a branch of the Tokyo Astronomical Observatory, University of Tokyo, is a cosmic radio observing facility open to outside users. 相似文献
2.
A logN — logS relation at 10 GHz is constructed for sources with the flat spectra 0.5 (flux densitySv
–) from observations at NRO, MPIfR and others. Based on the source distribution on log (Luminosity) volume plane we obtain an epoch-depending luminosity function which explains the above relation.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.Nobeyama Radio Observatory, a branch of the Tokyo Astronomical Observatory, University of Tokyo, is a facility open for general use by researchers in the field of astronomy and astrophysics. 相似文献
3.
We present high resolution CS and CO maps of Cep A region made with the 45m telescope at Nobeyama. The CS map shows that a dense cloud surrounding the proto-star cluster extends in the North-South direction and is probably rotating. The bipolar molecular flow apparent in the CO maps is well-collimated along East-West direction within 0.2 pc from the proto-stars. The dense cloud is gravitationally unstable and appears to be in a contracting phase to form a cluster of massive stars.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.NRO, a branch of the Tokyo Astronomical Observatory, University of Tokyo, is a cosmic radio observing facility open for outside users. 相似文献
4.
A ring of compact radio continuum sources was found atl=24°.6b=0°.0, which we call the Scutum ring. Radio continuum,Hi line, and CO line observations are suggested that it is a star-forming region triggered by an expanding diffuseHii region.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.NRO, a branch of the Tokyo Astronomical Observatory, University of Tokyo, is a cosmic radio observing facility open for outside users. 相似文献
5.
Yoshihisa Irimajiri Toshiaki Takano Hiroshi Nakajima Kiyoto Shibasaki Yoichiro Hanaoka Kiyoshi Ichimoto 《Solar physics》1995,156(2):363-375
Radio images and spectra of an eruptive prominence were obtained from simultaneous multifrequency observations at 36 GHz, 89 GHz, and 110 GHz on May 28, 1991 with the 45-m radio telescope at Nobeyama Radio Observatory (NRO), the National Astronomical Observatory, Japan (NAOJ). The radio spectra indicated that the optical depth is rather thick at 36 GHz whereas it is thin at 89 and 110 GHz. The H data, taken at Norikura Solar Observatory, NAOJ, suggest that the eruption of an active region filament was triggered by an H flare. The shape and position of the radio prominence generally coincided with those of H images. The radio emission is explained with an isothermal cool thread model. A lower limit for the electron temperature of the cool threads is estimated to be 6100 K. The range of the surface filling factors of the cool threads is 0.3–1.0 after the H flare, and 0.2–0.5 in the descending phase of the eruptive prominence. The column emission measure and the electron number density are estimated to be of the order of 1028 cm–5 and 1010 cm–3, respectively. The physical parameters of a quiescent prominence are also estimated from the observations. The filling factors of the eruptive prominence are smaller than those of the quiescent prominence, whereas the emission measures and the electron densities are similar. These facts imply that each cool thread of the prominence did not expand after the eruption, while the total volume of the prominence increased. 相似文献
6.
The results of new spectral observations of the Seyfert component of the close binary galaxy with UV excess Kaz 163 are presented. Two new spectra have been obtained: with the 3-m telescope of Lick Observatory in 1986 and with the 1.8-m telescope of Asiago Observatory in 1993. It is shown that there was no short-term (about one month) variability in the spectrum. The emission lines Hell 4686 and Hel 5876 strengthen significantly between 1984 and 1986.Translated fromAstrofizika, Vol. 37, No. 1, pp. 5–12, January–March, 1994. 相似文献
7.
A new model for solar spike bursts is considered based on the interaction of Langmuir waves with ion-sound waves: l+st. Such a mechanism can operate in shock fronts, propagating from a magnetic reconnection region. New observations of microwave millisecond spikes are discussed. They have been observed in two events: 4 November 1997 between 05:52–06:10 UT and 28 November 1997 between 05:00–05:10 UT using the multichannel spectrograph in the range 2.6–3.8 GHz of Beijing AO. Yohkoh/SXT images in the AR and SOHO EIT images testify to a reconstruction of bright loops after the escape of a CME. A fast shock front might be manifested as a very bright line in T
e SXT maps (up to 20 MK) above dense structures in emission measure (EM) maps. Moreover one can see at the moment of spike emission (for the 28 November 1997 event) an additional maximum at the loop top on the HXR map in the AR as principal evidence of fast shock propagation. The model gives the ordinary mode of spike emission. Sometimes we observed a different polarization of microwave spikes that might be connected with the depolarization of the emission in the transverse magnetic field and rather in the vanishing magnetic field in the middle of the QT region. Duration and frequency band of isolated spikes are connected with parameters of fast particle beams and shock front. Millisecond microwave spikes are probably a unique manifestation of flare fast shocks in the radio emission. 相似文献
8.
D. N. B. Hall 《Astrophysics and Space Science》1989,160(1-2):243-248
The characteristics of the Mauna Kea site are reviewed. An extensive site survey by NOAO during 1984–1985 showed that the average seeing was in the 0.4–0.6 range and thatr
0 was approximately 30 cm. An image quality study at the UH 88-inch telescope in 1987 showed the free atmosphere seeing was 0.5 and the boundary layer contributed less than 0.25.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988. 相似文献
9.
Nagayoshi Ohashi Ryohei Kawabe Masato Ishiguro Masahiko Hayashi 《Astrophysics and Space Science》1994,212(1-2):239-250
The Nobeyama Millimeter Array Survey for protoplanetary disks has been made for 19 protostellar IRAS sources in Taurus; 13 of them were optically invisible protostars and 6 were young T Tauri stars. We observed 98-GHz continuum and CS(J = 2 – 1) line emissions simultaneously with spatial resolutions of 2
.
8-8
.
8 (360-1,200 AU). The continuum emission was detected from 5 out of 6 T Tauri stars and 2 out of 13 protostar candidates: the emission was not spatially resolved and was consistent with being originated from compact circumstellar disks. Extended CS emission was detected around 2 T Tauri stars and 11 protostar candidates. There is a remarkable tendency for the detectability of the 98-GHz continuum emission to be small for protostar candidates. This tendency is explained if the mass of protoplanetary disks around protostars is not as large as that around T Tauri stars; the disk mass may increase with the increase of central stellar mass by dynamical accretion in the course of evolution from protostars to T Tauri stars.Paper presented at the Conference onPlanetary Systems: Formation, Evolution, and Detection held 7–10 December, 1992 at CalTech, Pasadena, California, U.S.A. 相似文献
10.
We argue that the polarised optical emission from AM Herculis-type systems arises from a compact high temperature (T10 keV) region closely associated with the accretion shock.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984. 相似文献
11.
Two-dimensional evolutions of two flares of October 18, 1990 have been well observed in the Caii K line with a CCD camera at Norikura station of National Astronomical Observatory in Japan. There are two common characteristics for the flares: 3 - 5 min before the impulsive phase, the heating already begins at the footpoints of the flares, but no asymmetry in line emission has been detected. After the onset of the impulsive phase, Caii K line emission at the footpoints shows strong red asymmetry, with the maximum asymmetry occurring at the same time as the peak of the radio bursts. The maximum downward velocity is about 30 50 km s–1. For flare 1, blue and red asymmetries were observed in two sides of the footpoint area. They developed and attained a maximum nearly at the same time and the inferred Doppler velocities are comparable (30 40 km s–1). This implies that two mass jets started from a small region and ejected along a loop but in opposite directions with roughly equivalent momentum. A possible mechanism has been discussed. 相似文献
12.
L. Verdes-Montenegro J. M. Torrelles L. F. Rodriguez G. Anglada R. Lopez R. Estallella J. Canto P. T. P. Ho 《Astrophysics and Space Science》1990,171(1-2):161-162
The (J, K)=(1,1) ammonia transition emission has been observed toward six regions with signs of active star formation (AFGL 5142, HH 33/40, AFGL 5157, AFGL 6366S, HHL 73, and S140N), using the 37 m antenna of the Haystack Observatory. We detected and mapped the ammonia emission in all of these sources with the exception of HH 33/40. The (J, K)-(2,2), ammonia transition was also observed at the peak position of each source in order to obtain the rotational temperature of the ammonia clumps.Paper presented at the 11th European regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain. 相似文献
13.
Mahipal Singh 《Astrophysics and Space Science》1982,87(1-2):269-277
The H profile in the spectrum of Orionis shows phase-dependent changes, with a period of variation equal to the orbital period fo the binary system. The profile shape changes from a normal absorption profile at zero phase to a P Cygni-type at a later phase, to an absorption profile having emission at the centre of the profile, to a normal absorption profile at the end of the period. The spectra have been obtained at the Cassegrain focus of Kavalur Observatory telescopes (50 and 100 cm) at 17.2 Å mm–1 reciprocal dispersion and resolution 0.3 Å at 6562.817 Å. Assuming that the P Cygni profile is formed by a spherically-symmetrical region, the analysis gives a shell radius of 2.18 stellar radius and an electron density in the shell equal to 6.54×10–9 cm–3, with the observed expansion velocity of 50 km/s–1, a mass loss of 1.3×10–7
M
per year.An analysis has been carried on the radial velocity data of earlier observers and the present radial velocity data. It is found that the orbital elements change. The presence of apsidal motion is confirmed by the increasing value of . The radial velocity of the centre of mass, , shows periodic variation. These observations confirm the presence of a third body. The values ofK (mean amplitude),P (period),a sini, and mass functionf(m), indicate a regular decrease, thereby confirming the mass transfer/mass loss from the system. 相似文献
14.
The C.C.W. method has been used to investigate the propagation of converging and diverging cylindrical shock waves in a non-uniform medium under the influence of a magnetic field of constant strength. A comparison has also been made between the two types of cylindrical shock waves, simultaneously for both weak and strong cases of the magnetic field. Density distribution is assumed to be
o =
r
–, where
is the density at the axis of symmetry and a constant. The analytical expressions for shock velocity and shock strength as well as the pressure, the density, and the particle velocity just behind the shock front have been derived for both the cases. 相似文献
15.
The effect of shock wave propagation is investigated with respect to precursor heating and acceleration, upstream, with the aim of explaining Supernova (SN) observations.A model is presented, where two different sources of Langmuir waves produce upstream heating and acceleration: (1) Langmuir waves excited by resonance beam particles, that are accelerated through the shock front by Bell's mechanism; and (2) Langmuir waves, created in the post-shock turbulent zone.The most important processes considered in the calculations are: (1) the heating efficiency of beam particles of different velocity; (2) Bell's acceleration efficiency; (3) the spectrum of Langmuir waves created in a turbulent regime; (4) the effects of density, and of the density gradient in the medium, where the shock propagates.The calculations are applied to type II SN. The results show that temperatures of 105–106 K, obtained in the preshock region, can explain P-Cygni observed line profiles. Moreover, accelerations of the plasma in front of the shock up tov108 cm s–1 by momentum exchange, are in good agreement with observations.Partially supported by Conselho Nacional de Desenvolvimento Cientifico e Technológico (CNPq) and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP). 相似文献
16.
Results of a search for new H objects in the Cepheus region are presented. The observations on which the search was based were made in 1979 and 1985 at the 40 Schmidt telescope of the Byurakan Astrophysical Observatory with a 4° objective prism. Of the 80 emission stars detected, 68 are new. Most of them are fainter than the sun in absolute magnitude. A large fraction of the emission stars discovered may be flare stars as well as T Tau and Herbig Ae/Be stars.Translated fromAstrofizika, Vol. 39, No. 1, pp. 57–65, January–March, 1996. 相似文献
17.
A group of type III bursts observed with the 2.6–3.8 GHz spectrometer of National Astronomical Observatory of China on 15 April 1998 is analyzed. They have the characteristics of broad bandwidth (>100 MHz), very short durations (<100 ms), high polarization degree (100%), high frequency drift rates (>1 GHz s–1), and fast pulsations (with a period of about 100–200 ms). Their time profiles are also analysed. According to these characteristics, we suggest that these microwave type III bursts may be due to the fundamental plasma emission. 相似文献
18.
M. Barsony D. Sasselov S. Rucinski E. Bloemhof L. -A. Nyman 《Astrophysics and Space Science》1995,233(1-2):51-54
We present new images of the well-known molecular outflow and Herbig-Haro complex L 1551-IRS 5. Deep, high-resolution images of the central region of the flow in [SII] 6716,6731 and H (6565 Å) are complemented by a mosaic of much of the CO outflow in H2 v=1-0 S(1). While the optical data trace the intermediate-to-high excitation shocks in the flow (v
shock
> 30 – 50 km s–1), the near-IR data reveal the lower-excitation, molecular shocks (v
shock
10–50 km s–1). In particular, the H2 data highlight the regions where the flow impacts and shocks ambient molecular gas. 相似文献
19.
V. V. Krymkin 《Astrophysics and Space Science》1978,58(2):347-352
Observations of the ionized hydrogen region NGC 1499 have been carried out with the radio telescope UTR-2 at frequencies 12.6, 14.7, 16.7, 20 and 25 MHz. The half-power resolution of the instrument to zenith is 28×34 at 25 MHz. The average volume density of the non-thermal radio emission between the Sun and the nebula (1.75×10–40 W m–3 Hz–1 ster–1 at 25 MHz), the electron temperature of the HII nebula (T
e
=4400 K), the measure of emission (ME=1500 cm–6 pc) and other parameters have been obtained. Maps of brightness distribution over the source are presented for each observation frequency. The results are compared with previously obtained data. 相似文献
20.
Linear correlations between the diameter log of ring-shaped nebulae and the total number logN of embedded stars for two absolute magnitude levels of –2m and +2m for the LMC have been found. This shows that less luminous stars are also contributing towards the illumination of the nebulae. A method for the determination of relative ages of these loop nebulae is described.Based on observations collected at the Boyden Observatory, Bloemfontein, South Africa and the European Southern Observatory, La Silla, Chile. 相似文献