Filtered CCD images of southern Herbig-Haro objects

HH39 is the group of Herbig-Haro (HH) objects associated with the young semi-stellar object R Monocerotis (R Mon) and the variable reflection nebula NGC 2261. An R CCD frame and a B prime focus plate of the region show a filament connecting NGC 2261 with HH39, confirming the association between R Mon and the HH objects. This filament is probably composed of emission material. The southern knot in HH39 has brightened over the last 20 years; its proper motion has been determined and is similar to that of the other knots. A total of 8 knots can be distinguished in HH39 surrounded by diffuse nebulosity. High resolution spectroscopy of the Hα and [N II] emission lines shows the spatial variation of the radial velocity structure over the largest knots (HH39 A and C). Distinct differences in excitation and velocity structure between the knots are apparent. The observations are compatible with the knots being high velocity ejecta from R Mon, decelerated by interaction with ambient material and with bow shocks on their front surfaces.

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The Wisconsin Hα Mapper (WHAM): A Brief Review of Performance Characteristics and Early Scientific Results

Publications of the Astronomical Society of Australia ◽

10.1071/as98014 ◽

1998 ◽

Vol 15 (1) ◽

pp. 14-18 ◽

Cited By ~ 88

Author(s):

R. J. Reynolds ◽

S. L. Tufte ◽

L. M. Haffner ◽

K. Jaehnig ◽

J. W. Percival

Keyword(s):

High Velocity ◽

Optical Emission ◽

Emission Lines ◽

Spectral Window ◽

Sky Surveys ◽

Early Results ◽

Fabry Perot ◽

The Galaxy ◽

High Velocity Clouds ◽

Scientific Results

Abstract. The Wisconsin Hα Mapper (WHAM) is a recently completed facility for the detection and study of faint optical emission lines from diffuse ionised gas in the disk and halo of the Galaxy. WHAM consists of a 15 cm diameter Fabry–Perot spectrometer coupled to a 0·6 m ‘telescope’, which provide a 1° diameter beam on the sky and produce a 12 km s−1 resolution spectrum within a 200 km s−1 spectral window. This facility is now located at Kitt Peak in Arizona and operated remotely from Madison, Wisconsin, 2400 km distant. Early results include a velocity-resolved Hα map of a 70° × 100° region of the sky near the Galactic anticentre, the first detections of Hα emission from the M I and A high velocity clouds, and the first detections of [O I] λ6300 and other faint ‘diagnostic’ lines from the warm ionised medium. Through the summer of 1998, WHAM will be devoted almost exclusively to a survey of the northern sky, which will provide maps of the distribution and kinematics of the diffuse HII through the optical Hα line in a manner that is analogous to earlier sky surveys of the HI made through the 21 cm line.

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Kinematics of Nuclei of Sc Galaxies

Highlights of Astronomy ◽

10.1017/s1539299600003890 ◽

1980 ◽

Vol 5 ◽

pp. 191-191

Author(s):

V. C. Rubin

Keyword(s):

High Velocity ◽

Stellar Population ◽

Hii Regions ◽

Emission Lines ◽

High Luminosity ◽

Rotation Curves ◽

Velocity Gradients ◽

Wide Range ◽

Central Regions ◽

Velocity Dispersions

For a sample of 21 Sc galaxies with a wide range of luminosities, of radii, and of masses, W. K. Ford and I have obtained spectra and determined rotation curves. By their kinematical behavior in their central regions, the Sc’s can be separated into two groups. Some galaxies, generally small and of low luminosity, have shallow central velocity gradients, reflecting their low central masses and densities. Other galaxies, most often large ones of high luminosity, have steep central velocity gradients. One reason this separation by central velocity gradients is of interest is because these galaxies exhibit other significant spectral differences which go hand-in-hand with the kinematical differences.The small, low luminosity galaxies show emission lines of Hα and [NII], with nuclear Ha sharp and stronger than [NII], and little or no stellar nuclear continuum, just as conventional HII regions. In contrast, the high luminosity galaxies show broad nuclear emission, with [NII] stronger than Ha. These galaxies have a strong red stellar continuum, arising from a red stellar population. The cause of the Hα[NII] intensity reversal in the nuclei of some galaxies remains unknown. However, the strong [NII] emission in generally high luminosity galaxies with massive nuclei, nuclei which show strong red continua, suggests that [Nil] intensity correlates with nuclear luminosity, and in turn with the density and velocity properties of the nuclear populations. We would expect high velocity dispersions and high bulge luminosities for galaxies with strong nuclear [NII] and steep central velocity gradients.

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Shocked Molecular Hydrogen from Star Forming Regions

Symposium - International Astronomical Union ◽

10.1017/s0074180900095371 ◽

1987 ◽

Vol 115 ◽

pp. 181-181 ◽

Cited By ~ 2

Author(s):

Adair P. Lane ◽

John Bally

Keyword(s):

Shock Waves ◽

High Velocity ◽

Molecular Hydrogen ◽

Near Infrared ◽

Young Stars ◽

Emission Lines ◽

Molecular Gas ◽

Star Forming ◽

Star Forming Regions ◽

Post Shock

Near infrared (2 micron) emission lines from molecular hydrogen provide a powerful probe of the morphology and energetics of outflows associated with stellar birth. The H2 emission regions trace the location of shock waves formed when the high velocity outflow from young stars encounters dense quiescent gas. Since H2 is the dominant coolant of the hot post-shock molecular gas, the H2 lines provide a measure of the fraction of the total mechanical luminosity radiated away from the cloud.

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The Molecular Outflow and CO Bullets in HH111

Symposium - International Astronomical Union ◽

10.1017/s0074180900061611 ◽

1997 ◽

Vol 182 ◽

pp. 141-152 ◽

Cited By ~ 1

Author(s):

J. Cernicharo ◽

R. Neri ◽

Bo Reipurth

Keyword(s):

High Velocity ◽

Angular Resolution ◽

High Angular Resolution ◽

Molecular Gas ◽

Kinetic Temperature ◽

Low Velocity ◽

Molecular Outflow ◽

Hh Objects ◽

Physical Phenomena ◽

First Time

We present high angular resolution observations of the molecular outflow associated with the optical jet and HH objects of the HH111 system. Interferometric observations in the CO J =2–1 and J =1–0 lines of the high velocity bullets associated with HH111 are presented for the first time. The molecular gas in these high velocity clumps has a moderate kinetic temperature and a mass of a few 10–4 M⊙ per bullet. We favor the view that HH jets and CO bullets, which represent different manifestations of the same physical phenomena, are driving the low-velocity molecular outflow.

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Molecular gas around the Wolf-Rayet star WR 18 (WN4)

Symposium - International Astronomical Union ◽

10.1017/s0074180900213260 ◽

2003 ◽

Vol 212 ◽

pp. 732-733

Author(s):

Anthony P. Marston

Keyword(s):

Mass Loss ◽

Optical Emission ◽

Emission Lines ◽

Molecular Gas ◽

Evolved Stars ◽

Ring Nebula ◽

History Of ◽

Optical Ring ◽

Ring Nebulae ◽

Rayet Star

Optically observed ring nebulae and H i cavities around Wolf-Rayet stars have enabled us to obtain information on the history of mass-loss associated with these massive evolved stars. However, such studies have left a number of unanswered questions regarding the amount of mass-loss and the conditions of the stars during a sequence of mass-loss phases. Here we discuss the molecular gas environments of the WR star WR 18, which has an associated optical ring nebula NGC 3199. Our observations show that significant amounts of molecular gas appear close to and associated with the star. Mapping of molecular CO near the star shows that molecular materials appear to substantially avoid areas of optical emission and, instead, form a distorted clumpy shell interior to NGC 3199. Molecular emission lines are broader than lines seen in the interstellar medium and suggest the shell is composed of ejecta. This is further corroborated by the enhanced abundances of molecules containing C, N and O. Implications of the observations for the evolution of WR 18 are discussed.

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Colliding Stellar Winds in O-type Close Binary Systems

International Astronomical Union Colloquium ◽

10.1017/s0252921100006254 ◽

1992 ◽

Vol 135 ◽

pp. 146-148

Author(s):

D.R. Gies ◽

M.S. Wiggs

Keyword(s):

Binary Systems ◽

Optical Emission ◽

Emission Lines ◽

Optical Observations ◽

Close Binary ◽

High Dispersion ◽

Stellar Winds ◽

Close Binary Systems ◽

Circumstellar Gas ◽

The Individual

In close binary systems of O-type stars, the individual stellar winds will collide between the stars to form shock fronts (Stevens et al. 1992). Binaries with equally luminous stars will have winds of comparable strength, and the shock will occur near the mid-plane between the stars, but in binaries of unequal luminosity, the interaction will occur along a bow shock wrapped around the star with the weaker wind. The presence of the shock region can be detected through excess X-ray emission (Chlebowski & Garmany 1990), and orbital phase-related variations in the UV P Cygni lines (Shore & Brown 1988) and optical emission lines (formed in high density regions of circumstellar gas).We have begun a search for colliding winds through a study of the optical emission lines and UV P Cygni lines in four massive binaries, AO Cas (Gies & Wiggs 1991), Plaskett’s star = HD 47129 (Wiggs & Gies 1992), 29 UW CMa and ι Ori. The optical observations consist of high S/N spectra of the Hα and He I λ6678 region obtained with the University of Texas McDonald Observatory 2.1-m telescope and coudé Reticon system. The UV observations were culled from archival IUE high dispersion spectra of several P Cygni features (N V λ1240, Si IV λ1400, C IV λ1550).

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Discovery of diffuse optical emission lines from the inner Galaxy: Evidence for LI(N)ER-like gas

Science Advances ◽

10.1126/sciadv.aay9711 ◽

2020 ◽

Vol 6 (27) ◽

pp. eaay9711 ◽

Cited By ~ 2

Author(s):

D. Krishnarao ◽

R. A. Benjamin ◽

L. M. Haffner

Keyword(s):

Active Galactic Nuclei ◽

Galactic Center ◽

Line Emission ◽

Galactic Nuclei ◽

Optical Emission ◽

Hydrogen Gas ◽

Emission Lines ◽

Neutral Gas ◽

Optical Line ◽

Tilted Disk

Optical emission lines are used to categorize galaxies into three groups according to their dominant central radiation source: active galactic nuclei, star formation, or low-ionization (nuclear) emission regions [LI(N)ERs] that may trace ionizing radiation from older stellar populations. Using the Wisconsin H-Alpha Mapper, we detect optical line emission in low-extinction windows within eight degrees of Galactic Center. The emission is associated with the 1.5-kiloparsec-radius “Tilted Disk” of neutral gas. We modify a model of this disk and find that the hydrogen gas observed is at least 48% ionized. The ratio [NII] λ6584 angstroms/Hα λ6563 angstroms increases from 0.3 to 2.5 with Galactocentric radius; [OIII] λ5007 angstroms and Hβ λ4861 angstroms are also sometimes detected. The line ratios for most Tilted Disk sightlines are characteristic of LI(N)ER galaxies.

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