Study of the HII regions in the spiral galaxy NGC6384

VLA observations of the spiral galaxy M81 in the radio continuum at wavelengths of 6 and 20-cm have been used to check the predictions of the density wave theory. The non-thermal radiation from the arms has been detected and the arms are found to be broader than the predictions of the classical density wave theory. Their width does seem to agree with that predicted by models which take the clumpy nature of the interstellar medium into account. These data are also able to separate giant HII regions from the non-thermal arms. Collaborators have furnished optical Hα data on the HII regions and HI 21-cm data, from the VLA, which will be used to find and measure the location of the HII regions with respect to the spiral shock wave and to measure the visual extinction in the disk of M81.

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The Nature, Location and Environment of Sgr A East

Symposium - International Astronomical Union ◽

10.1017/s0074180900186723 ◽

1989 ◽

Vol 136 ◽

pp. 345-356 ◽

Cited By ~ 1

Author(s):

W. M. Goss ◽

K. R. Anantharamaiah ◽

J. H. van Gorkom ◽

R. D. Ekers ◽

A. Pedlar ◽

...

Keyword(s):

Spiral Galaxy ◽

Molecular Cloud ◽

Supernova Remnant ◽

Galactic Center ◽

Hii Regions ◽

Active Nucleus ◽

The Galaxy ◽

Sgr A ◽

Turn Over ◽

Unique Variation

We have observed SgrA at 332 MHz (92 cm) with a resolution of 12 arcsec (0.6 pc) using the four configurations of the VIA. These results illustrate the dramatic and almost unique variation of radio spectral index within the central 3–4 arcmin of the galactic center. SgrA East is a non-thermal shell source that could be a supernova remnant or a very low-luminosity example of a radio component associated with the active nucleus of a spiral galaxy. The most dramatic aspect of the new 332 MHz observations is the appearance of the the SgrA West spiral features in absorption against SgrA East. Based on these results, SgrA East is situated behind SgrA West, the center of the galaxy. The halo is in front of or surrounds the former sources. The HII regions to the east of SgrA East (1 = −0°.02, b = −0°.07) are probably associated with the 50 km/s molecular cloud. The 7 arcmin halo (20 pc) has a non-thermal spectrum with turn-over below 1 GHz.

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Optical observations of the nearby galaxy IC342 with narrow band [SII] and Hα filters. I

Serbian Astronomical Journal ◽

10.2298/saj1387011v ◽

2013 ◽

pp. 11-18 ◽

Cited By ~ 2

Author(s):

M.M. Vucetic ◽

B. Arbutina ◽

D. Urosevic ◽

A. Dobardzic ◽

M.Z. Pavlovic ◽

...

Keyword(s):

Spiral Galaxy ◽

Narrow Band ◽

Hii Regions ◽

Astronomical Observatory ◽

Optical Observations ◽

Nearby Galaxy ◽

The Galaxy

We present observations of a portion of the nearby spiral galaxy IC342 using narrow band [SII] and H? filters. These observations were carried out in November 2011 with the 2m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper we report coordinates, diameters, H? and [SII] fluxes for 203 HII regions detected in two fields of view in IC342 galaxy. The number of detected HII regions is 5 times higher than previously known in these two parts of the galaxy.

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Spatially-Resolved Internal Kinematics of 〈z〉 ≈ 0.3 Field Galaxies: Evidence for Rotation

Symposium - International Astronomical Union ◽

10.1017/s0074180900233044 ◽

1996 ◽

Vol 171 ◽

pp. 385-385

Author(s):

P. Guhathakurta ◽

K. Ing ◽

H.-W. Rix ◽

M. Colless ◽

T. Williams

Keyword(s):

Emission Line ◽

Spiral Galaxy ◽

Rotation Speed ◽

Hii Regions ◽

Reliable Measure ◽

Spatially Resolved ◽

Distant Galaxies ◽

Distant Field ◽

Fisher Relation ◽

Luminosity Evolution

The nature of evolution in faint field galaxies remains a mystery. The Tully-Fisher relation, empirically relating the intrinsic luminosity of a spiral galaxy to its rotation speed, is an important tool for constraining the amount of luminosity evolution in distant field galaxies. Studying the luminosity-vs-linewidth relation for distant galaxies allows one to compare the luminosity of local and distant galaxies. The customary measure of a galaxy's rotation speed is the width of an emission line. It is important, however, to test whether the linewidth is a reliable measure of the galaxy's rotation speed or if it is dominated by turbulent motion within HII regions. In order to do this, we study the spatially-resolved kinematics and distribution of 0[III] gas in about ten 〈B〉∼21 field galaxies at 〈z〉≈0.3.

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Spectroscopic study of the HII regions in the NGC 1232 galaxy

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038088 ◽

2020 ◽

Vol 642 ◽

pp. A203

Author(s):

F. Lima-Costa ◽

L. P. Martins ◽

A. Rodríguez-Ardila ◽

L. Fraga

Keyword(s):

Star Formation ◽

Spiral Galaxy ◽

Stellar Population ◽

Spiral Galaxies ◽

Hii Regions ◽

Emission Lines ◽

Starburst Galaxy ◽

Abundance Gradient ◽

Significant Difference ◽

The Galaxy

Context. NGC 1232 is a face-on spiral galaxy that serves as an excellent laboratory for the study of star formation due to its proximity. Recent studies have revealed interesting features about this galaxy: X-ray observations suggest that it recently collided with a dwarf galaxy, however, no apparent remnant is observed. Aims. In this study, we search for evidence of this possible collision. Methods. We used long-slit optical spectra of the galaxy in two different positions obtained with the Goodman spectrograph at the SOAR telescope. Results. We detected 18 HII regions in the north-south direction and 22 HII regions in the east-west direction and a background galaxy, NGC 1232B, for which we present the first redshift measurement and spectral analysis. We used the stellar population fitting technique to study the underlying stellar population of NGC 1232 and NGC 1232B and to subtract it from the spectra to measure the emission lines. The emission lines were used to determine the extinction, electron density, chemical abundance, and the star-formation rate gradient of NGC 1232. Conclusions. As is common in spiral galaxies, we found a stellar population gradient with older populations at the central regions and younger ones towards the outskirts, along with a negative oxygen abundance gradient of −0.16 dex/re. Due to the difficulty of measuring important emission lines, the number of objects for the abundance gradient is small, but there is a hint that this galaxy has a broken gradient profile, with a drop towards the center. Some authors have explained this effect as the result of a satellite collision, but observations of a large sample of spiral galaxies shows evidence that goes against such a mechanism. If the collision caused any disturbance in the galaxy, we believe it would be small and hard to detect with a limited number of objects. From all the other measurements, we found no deviations from a typical spiral galaxy and no significant difference between different directions in the galaxy. The stellar population and emission line analysis of NGC 1232B suggest that it is a starburst galaxy.

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HII REGIONS IN THE SPIRAL GALAXY NGC 3389

Journal of The Korean Astronomical Society ◽

10.5303/jkas.2003.36.2.049 ◽

2003 ◽

Vol 36 (2) ◽

pp. 49-54

Author(s):

ABDEL-HAMID HAMED ◽

SANG-GAK LEE ◽

PETER NOTNI

Keyword(s):

Spiral Galaxy ◽

Hii Regions

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BLACK HOLE EJECTED FROM THE NUCLEUS OF GALAXY NGC 5236

International Journal of Modern Physics D ◽

10.1142/s0218271810017494 ◽

2010 ◽

Vol 19 (08n10) ◽

pp. 1259-1264

Author(s):

H. DOTTORI ◽

R. DÍAZ ◽

J. F. ALBACETE-COLOMBO ◽

D. MAST

Keyword(s):

Black Hole ◽

Emission Line ◽

Optical Spectroscopy ◽

Spiral Galaxy ◽

Hii Regions ◽

X Ray ◽

Barred Spiral Galaxy

The Fanaroff–Riley II-type radiosource J 133658.3-295105, which is also an X-ray source, appears to be projected onto the disc of the barred-spiral galaxy NGC 5236 (M 83) at about 1.2 kiloparsecs from the galaxy's optical nucleus. J 133658.3-295105, its radio-lobes, and two other radiosources, neither of which are supernovae remnants or HII regions, are aligned with the optical nucleus of NGC 5236. Due to this peculiar on-the-sky projection, we studied J 133658.3-295105 using GEMINI+GMOS optical spectroscopy and also reanalyzed Chandra spectroscopy which was carried out in 2000. We marginally detected the H α emission line receding at 130 km/sec with respect to the optical nucleus. We also demostrate that J 133658.3-295105 presents the Fe–K α emission line at a redshift z = 0.018 ± 0.01. Both, H α and Fe–K α present redshifts that are compatible with the distance of NGC 5236. That findings reinforce the scenario of a local object for J 133658.3-295105, which could have been ejected from the nucleus of NGC 5236.

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