Double-peaked Balmer line emission in the radio-quiet AGN RX J1042 + 1212

The ROSAT Wide Field Camera all-sky EUV survey of 1990-91 identified over 200 active late-type stars (Pounds et al. 1993). Most of these were not known to be active prior to the survey and follow-up optical spectroscopy has been successful in selecting the most active dMe stars. These stars are characterized by their Balmer line emission which is direct evidence for an active chromosphere. We present photometric monitoring data for 4 new dMe stars, including the discovery of flaring activity on all 4 stars.The observations were made at the South African Astronomical Observatory at Sutherland near Capetown in October 1994, using the 0.5m and 1.9m telescopes for photometry and spectrometry, respectively. The 0.5m telescope is equipped with an automated, pulse-counting photometer. Flare monitoring of all the stars was done in the U-band with either 5 or 10 s integration times. All the stars monitored were between magnitude V = 11 and 13. A total of 15 flares were detected, including at least one on each star (Table 1). Comparison stars were measured in standard UBVRI photometric bands for each star.

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The influence of fast excited H fragments on balmer line emission cross section measurements for H2 and NH3 molecules

Chemical Physics ◽

10.1016/0301-0104(89)80247-2 ◽

1989 ◽

Vol 134 (1) ◽

pp. 163-172 ◽

Cited By ~ 4

Author(s):

Mirjana D. Tasić ◽

Zoran lj. Petrović ◽

Jelena M.Kurepa

Keyword(s):

Cross Section ◽

Emission Cross Section ◽

Line Emission ◽

Balmer Line

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Electron impact induced Balmer line emission from some aliphatic hydrocarbons

Chemical Physics ◽

10.1016/0301-0104(84)80061-0 ◽

1984 ◽

Vol 91 (2) ◽

pp. 273-283 ◽

Cited By ~ 11

Author(s):

J.M. Marendić ◽

M.D. Tasić ◽

J.M. Kurepa

Keyword(s):

Electron Impact ◽

Line Emission ◽

Aliphatic Hydrocarbons ◽

Balmer Line

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Broad Balmer line emission and cosmic ray acceleration efficiency in supernova remnant shocks

Astronomy and Astrophysics ◽

10.1051/0004-6361/201322006 ◽

2013 ◽

Vol 558 ◽

pp. A25 ◽

Cited By ~ 20

Author(s):

G. Morlino ◽

P. Blasi ◽

R. Bandiera ◽

E. Amato

Keyword(s):

Supernova Remnant ◽

Line Emission ◽

Cosmic Ray ◽

Balmer Line ◽

Cosmic Ray Acceleration

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Interpretation of Electric fields in Coronal Magnetic Loops

International Astronomical Union Colloquium ◽

10.1017/s0252921100085213 ◽

1984 ◽

Vol 86 ◽

pp. 25-28

Author(s):

P. Foukal ◽

D. Landman

Keyword(s):

Electric Fields ◽

Stark Effect ◽

Local Density ◽

Line Emission ◽

Thomson Scattering ◽

Balmer Line ◽

Flare Loops ◽

Coronal Magnetic Loops ◽

Order Of Magnitude ◽

The Difference

Stark effect detected in high Balmer lines emitted from flares, prominences, and quiet chromosphere is generally interpreted as pressure broadening in a plasma of relatively high density. But a recent study of post-flare loops indicates that the densities of order 1012 cm−3 required to explain the observed Balmer line broadening are an order of magnitude higher than values derived using other plasma diagnostics such as Thomson scattering and Balmer line emission measures (Foukal, Miller, and Gilliam 1983). The disagreement might be explained as the difference expected between the true local density (measured by the Stark effect) in the obviously inhomogeneous loop plasma, and the straight mean or root mean square densities measured by Thomson scattering and line emission measures. More interestingly, the disagreement might imply a macroscopic electric field generated by, e.g., plasma waves in coronal magnetic loops.

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Interacting Nuclei in Distant Galaxies

International Astronomical Union Colloquium ◽

10.1017/s0252921100005170 ◽

1990 ◽

Vol 124 ◽

pp. 251-253

Author(s):

Wei Zheng ◽

Steven A. Grandi

Keyword(s):

Emission Line ◽

Active Galactic Nuclei ◽

Accretion Disk ◽

Outer Part ◽

Line Emission ◽

Galactic Nuclei ◽

Balmer Line ◽

Line Profiles ◽

Double Peaks ◽

Distant Galaxies

The interaction of galaxies not only occurs in galactic scales, but also may be linked to the binary cores in active galactic galaxies. The presence of a binary in the center of galaxies was suggested by Begelman, Blandford and Rees (1980). Gaskell (1983) suggests that supermassive binaries may account for the observed structure of emission line profiles such as double peaks displaced by a significant velocity difference. Collin-Souffrin, et al. (1986) argue that line emission may be formed in the outer part of an accretion disk. The resultant profile, as expected from rotational motion, would be very broad and often possess a double-horn shape. However, the emission line profiles in most active galactic nuclei do not share such a resemblance, and there are only two reported cases, 3C390.3 (Pérez et al. 1987) and Arp102B (Chen, Halpern and Filippenko 1989), in which the broad Balmer line profile may be of such a shape. Therefore, the assumption for accretion disk is to be verified with care.

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Inference of molecular divertor density from filtered camera analysis of molecularly induced Balmer line emission during detachment in JET L-mode plasmas

Journal of Instrumentation ◽

10.1088/1748-0221/17/01/c01032 ◽

2022 ◽

Vol 17 (01) ◽

pp. C01032

Author(s):

J. Karhunen ◽

A. Holm ◽

B. Lomanowski ◽

V. Solokha ◽

S. Aleiferis ◽

...

Keyword(s):

Experimental Data ◽

Monte Carlo ◽

Line Emission ◽

Balmer Line ◽

Molecular Processes ◽

Local Electron ◽

Molecular Density ◽

Local Electron Density ◽

Molecular Databases ◽

Intensity Ratios

Abstract A previously presented Monte Carlo method for estimating local plasma conditions in 2D based on intensity ratios of deuterium Balmer D α , D γ and D ɛ lines was amended to consider also the D α and D γ emission contributions arising from molecular processes. The obtained estimates were used to infer the molecular divertor density with the help of the molecular databases of EIRENE. The method was benchmarked against EDGE2D-EIRENE simulations and observed to reproduce the molecularly induced emission fractions and the molecular divertor densities primarily within 25% of the references. Experimental analysis of a JET L-mode density scan suggested molecularly induced D α and D γ contributions of up to 60–70% and 20%, respectively, during the process of detachment. The independent estimates of the molecular divertor density inferred from the obtained molecularly induced D α and D γ intensities agree within uncertainties with each other. Both estimates show the molecular density increasing up to approximately 1.0–2.0 × 1020 m−3 at the outer strike point in deep detachment with its ratio to the local electron density agreeing with EDGE2D-EIRENE predictions within the scatter of the experimental data.

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