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We have obtained optical spectrophotometry of 11 HII regions in the polar ring of NGC 2685 (the Helix galaxy), and have used these data to study the physical characteristics of the polar-ring HII regions. The HII regions have normal spectra…

天体物理学 · 物理学 2009-10-30 Paul B. Eskridge , Richard W. Pogge

We have discovered a number of very small isolated HII regions 20-30 kpc from their nearest galaxy. The HII regions appear as tiny emission line dots (ELdots) in narrow band images obtained by the NOAO Survey for Ionization in Neutral Gas…

天体物理学 · 物理学 2007-05-23 E. V. Ryan-Weber , M. E. Putman , K. C. Freeman , G. R. Meurer , R. L. Webster

The extent to which the ISM in galaxies is well mixed is not yet settled. Measured metal abundances in the diffuse neutral gas of star--forming gas--rich dwarf galaxies are deficient with respect to that of the ionized gas. The reasons, if…

天体物理学 · 物理学 2015-11-11 Vianney Lebouteiller , Daniel Kunth

We derive oxygen abundances for a sample of 40 luminous (M_{B} < -19), star-forming, mostly disk, field galaxies with redshifts in the range 0.2 < z < 0.8$, with a median of <z> = 0.45. Oxygen abundances, relative to hydrogen, of the…

天体物理学 · 物理学 2009-11-11 M. Mouhcine , S. P. Bamford , A. Aragon-Salamanca , O. Nakamura

We considered two sequences of spiral galaxies with different shapes of the radial gas-phase oxygen abundance distributions from the galaxies in the MaNGA survey: (1) Galaxies in which the gradient is well approximated by a single linear…

星系天体物理 · 物理学 2024-01-02 L. S. Pilyugin , G. Tautvaisiene

Non-LTE abundances of magnesium, aluminum and sulfur are derived for a sample of 23 low-v \sin i stars belonging to six northern OB associations of the Galactic disk within 1 kpc of the Sun. The abundances are obtained from the fitting of…

天体物理学 · 物理学 2009-11-07 S. Daflon , K. Cunha , V. V. Smith , K. Butler

Context. The knowledge of abundance distributions is central to understanding the formation and evolution of galaxies. Most of the relations employed for the derivation of gas abundances have so far been derived from observations of outer…

星系天体物理 · 物理学 2018-01-24 M. Rodríguez-Baras , A. I. Díaz , F. F. Rosales-Ortega , S. F. Sánchez

We search for the maximum oxygen abundance in spiral galaxies. Because this maximum value is expected to occur in the centers of the most luminous galaxies, we have constructed the luminosity - central metallicity diagram for spiral…

天体物理学 · 物理学 2008-11-26 L. S. Pilyugin , T. X. Thuan , J. M. Vilchez

The oxygen abundances in the \HII regions of a sample of low surface brightness (LSB) disk galaxies are presented. In general, LSB galaxies are found to be metal poor ($Z < {1 \over 3} Z\solar$). Indeed, some LSB galaxies rival the lowest…

天体物理学 · 物理学 2009-10-22 Stacy McGaugh

This is the fifth paper in a series studying the stellar components, star formation histories, star formation rates and metallicities of a blue compact galaxy (BCG) sample. Based on our high-quality ground-based spectroscopic observations,…

天体物理学 · 物理学 2009-11-13 F. Shi , X. Kong , C. Li , F. Z. Cheng

Oxygen abundances are derived in a sample of 13 field F and G dwarfs and subgiants with metallicities in the range of -0.75 < [Fe/H] < +0.15. This is the same sample of stars for which boron abundances have been derived earlier from…

天体物理学 · 物理学 2009-11-06 Verne V. Smith , Katia Cunha , Jeremy R. King

The spectral characteristics throughout the dwarf irregular galaxy DDO 53 are studied. The results are very similar to those for other irregular galaxies: high excitation and low values of the [SII]/Halpha ratio. The most likely ionization…

天体物理学 · 物理学 2008-11-26 A. M. Hidalgo-Gamez

We characterise the oxygen abundance radial distribution of a sample of 102 spiral galaxies observed with VLT/MUSE using the O3N2 calibrator. The high spatial resolution of the data allows us to detect 14345 HII regions with the same image…

We examine whether there are deviations of the local central oxygen abundances in spiral galaxies from the general metallicity gradients. We compare the values of the central intersect oxygen abundances estimated from the metallicity…

星系天体物理 · 物理学 2024-07-02 L. S. Pilyugin , G. Tautvaisiene

We have obtained multi-object spectroscopy of H II regions in the spiral galaxy M51 with the Keck I telescope and the Low Resolution Imaging Spectrometer. For 10 objects we have detected the auroral line [N II] 5755, while [S III] 6312 has…

天体物理学 · 物理学 2008-11-26 Fabio Bresolin , Donald R. Garnett , Robert C. Kennicutt

(Shortened version) We report optical spectroscopy of 16 H II regions in NGC 1705 and [O III] 4363 detections for the first time in five H II regions. The resulting mean oxygen abundance derived directly from measured electron temperatures…

天体物理学 · 物理学 2009-11-10 Henry Lee , Evan D. Skillman

We present deep optical spectroscopy of eight HII regions located in the anticentre of the Milky Way. The spectra were obtained at the 10.4m GTC and 8.2m VLT. We determined Te([NII]) for all objects and Te([OIII]) for six of them. We also…

星系天体物理 · 物理学 2017-08-16 C. Esteban , X. Fang , J. Garcia-Rojas , L. Toribio San Cipriano

We propose an empirical sulphur abundance determination method based on the strong sulphur emission lines, [S II] 6716, 6731 and [S III] 9069, 9531 in H II regions. From a compilation of literature data we have made a calibration of sulphur…

天体物理学 · 物理学 2007-05-23 Tina Christensen , Lars Petersen , Peter Gammelgaard

We present deep spectrophotometry of several Hii regions in the nearby low-mass spiral galaxies NGC 300 and M33. The data have been taken with UVES and OSIRIS spectrographs attached to the 8m VLT and 10.4m GTC telescopes, respectively. We…

星系天体物理 · 物理学 2016-03-23 L. Toribio San Cipriano , J. García-Rojas , C. Esteban , F. Bresolin , M. Peimbert

We present a new set of weak-line abundances of HII regions in M81, based on Gemini Multi-Object Spectrograph (GMOS) observations. The aim is to derive plasma and abundance analysis for a sizable set of emission-line targets to study the…

星系天体物理 · 物理学 2014-09-05 Letizia Stanghellini , Laura Magrini , Viviana Casasola , Eva Villaver