scholarly journals Southern emission line flux standards

1997 ◽  
Vol 180 ◽  
pp. 20-20
Author(s):  
M. A. Dopita ◽  
C. T. Hua
Keyword(s):  
Emission Line ◽  
Supplement Series ◽  
Radial Velocities ◽  
Emission Lines ◽  
High Dispersion ◽  
Line Flux ◽  
Astrophysical Journal ◽  
Line Imaging

Absolute emission line imaging photometry is often made difficult by the absence of good flux standards. Even bright PN often show as much as 25between different authors, reflecting the varying techniques of observation. In order to correct this situation, we have made slitless absolute spectrophotometric observations at high dispersion of compact (!5 arc sec. diameter) PN drawn from the Acker al. (1992) Catalogue. The complete results will appear in the Astrophysical Journal Supplement Series in early 1997. This paper gives absolute Hα, Hβ line fluxes, equivalent widths, accurate radial velocities, and relative fluxes of a number of other emission lines for some 50 PN in the southern sky between 7hr and 17hr in R.A.

scholarly journals Ultraviolet Variability of the Symbiotic Star AG PEG

1988 ◽  
Vol 103 ◽  
pp. 263-264
Author(s):  
D. Chochol ◽  
Z. Komárek ◽  
A. Vittone
Keyword(s):  
Optical Spectra ◽  
Radial Velocities ◽  
Roche Lobe ◽  
Emission Lines ◽  
High Dispersion ◽  
Symbiotic Star ◽  
Observational Material

Symbiotic star AG Peg consists of a hot subdwarf with a WN6 spectrum and a cool M3 giant, which is not filling its Roche lobe (Boyarchuk 1967, 1985). A detailed study of profiles, equivalent widths and radial velocities of emission lines in optical spectra allowed Hutchings et al. (1975) to conclude that a hot subluminous star approximately 1 M⊙ rotates rapidly and ejects material which streams towards the cool M giant with the mass 3-4 M⊙. UV observations seems to support this model.UV observations provided from the databank of the IUE satellite were obtained in 1978–81 by different observers. The observational material consists of 12 high dispersion SWP spectra and covers the region 1200 – 2100 A. The spectra were reduced at Trieste observatory using standard IUESIPS package. The radial velocities of emission lines were measured on tracings and corrected for the motion of Earth and satellite.

scholarly journals High Luminosity F-K Stars Motions and Hα Emissions

1980 ◽  
Vol 51 ◽  
pp. 170-170
Author(s):  
J. Smolinski ◽  
J.L. Climenhaga ◽  
B.L. Harris
Keyword(s):  
Radial Velocity ◽  
Radial Velocities ◽  
Emission Lines ◽  
High Dispersion ◽  
Common Phenomenon ◽  
Line Profiles ◽  
High Luminosity ◽  
Regular Time ◽  
Time Variations

AbstractChanges and differences in radial velocities between neutral and ionized metals have been found for three F5-type supergiants: HD 231195, HD 10494, and HD 17971. Fifteen high dispersion coudé spectrograms (6 Å/mm) were used and 33 to 165 lines were measured on each. Semi-regular time variations up to about 8 km s-1 in radial velocity have been found. In addition, Hα line profiles for 8 high luminosity F-K stars have been analyzed. All of the stars show Ha emissions, variable in time, which is probably a common phenomenon in very luminous stars. Metallic emission lines with low excitation potentials, in particular the Ca I 6572.8 and the Fe I 6574.2 lines, are present in 5 of these stars.

scholarly journals Emission Lines of Northern Planetary Nebulae

2016 ◽  
Vol 12 (S323) ◽  
pp. 333-334
Author(s):  
Nazim Aksaker ◽  
Sinan K. Yerli ◽  
Ümit Kızıloğlu ◽  
Betül Atalay
Keyword(s):  
Emission Line ◽  
Supernova Remnants ◽  
Planetary Nebulae ◽  
Hii Regions ◽  
Emission Lines ◽  
Line Flux ◽  
Chemical Abundances ◽  
Data Set ◽  
Standard Data ◽  
Spectrometric Measurements

AbstractIn this work, we present results of long slit spectrophotometric emission line flux observations of selected planetary nebulae (PNe). We have measured absolute fluxes and equivalent widths (EW) of all observable emission lines. In addition to these observations, electron temperatures (Te), densities (Ne), and chemical abundances were also calculated. The main purpose of this work is to fill the gaps in emission line flux standards for the northern hemisphere. It is expected that the measured fluxes would be used as standard data set for further photometric and spectrometric measurements of HII regions, supernova remnants etc.

scholarly journals Emission Line Analyses of HBV 475, V1016 CYG, and HM SGE

1988 ◽  
Vol 103 ◽  
pp. 285-286
Author(s):  
S. Tamura
Keyword(s):  
Emission Line ◽  
Radial Velocities ◽  
High Dispersion ◽  
Symbiotic Stars ◽  
Spectroscopic Observations

AbstractResults of the high dispersion spectroscopic observations on HBV 475, V1016 Cyg, and HM Sge are presented. Due to yearly observations of HBV 475 since 1981, radial velocities which have been measured from Hα and Hγ can be explained by a bipolar like non-spherical flow combined with the rotation. Highly resolved profiles of Hα, [FeVII]λ6087, [0III] λλ4959,5007, and HeIIλ4686 are obtained from V1016 Cyg and HM Sge as well as HBV 475. Characteristic differences of them can be seen among these symbiotic stars.

scholarly journals Periodic Variations in the Symbiotic Star Spectra

1987 ◽  
Vol 93 ◽  
pp. 713-723 ◽  
Author(s):  
J. Mikolajewska
Keyword(s):  
Emission Line ◽  
Radial Velocities ◽  
Emission Lines ◽  
Symbiotic Star ◽  
Symbiotic Stars ◽  
Line Intensities ◽  
Physical Conditions

AbstractPeriodic variations of emission line intensities and radial velocities in three S-type symbiotic stars: BF Cyg, CI Cyg and AX Per are presented and discussed. The behavior of emission lines is different in these objects and suggests that significant differences in physical conditions and geometry may occur in these seemingly similar systems.

scholarly journals The synthetic Emission Line COSMOS catalogue: Hα and [O ii] galaxy luminosity functions and counts at 0.3 < z < 2.5

2020 ◽  
Vol 494 (1) ◽  
pp. 199-217
Author(s):  
Shun Saito ◽  
Sylvain de la Torre ◽  
Olivier Ilbert ◽  
Cédric Dubois ◽  
Kiyoto Yabe ◽  
...  
Keyword(s):  
Emission Line ◽  
Spectral Energy Distribution ◽  
Emission Lines ◽  
Spectral Energy ◽  
Next Generation ◽  
Line Flux ◽  
Redshift Surveys ◽  
Luminosity Functions ◽  
Galaxy Redshift ◽  
Dust Attenuation

ABSTRACT Star-forming galaxies with strong nebular and collisional emission lines are privileged target galaxies in forthcoming cosmological large galaxy redshift surveys. We use the COSMOS2015 photometric catalogue to model galaxy spectral energy distributions and emission-line fluxes. We adopt an empirical but physically motivated model that uses information from the best-fitting spectral energy distribution of stellar continuum to each galaxy. The emission-line flux model is calibrated and validated against direct flux measurements in subsets of galaxies that have 3D-HST or zCOSMOS-Bright spectra. We take a particular care in modelling dust attenuation such that our model can explain both Hα and [O ii] observed fluxes at different redshifts. We find that a simple solution to this is to introduce a redshift evolution in the dust attenuation fraction parameter, f = Estar(B − V)/Egas(B − V), as f(z) = 0.44 + 0.2z. From this catalogue, we derive the Hα and [O ii] luminosity functions up to redshifts of about 2.5 after carefully accounting for emission line flux and redshift errors. This allows us to make predictions for Hα and [O ii] galaxy number counts in next-generation cosmological redshift surveys. Our modelled emission lines and spectra in the COSMOS2015 catalogue shall be useful to study the target selection for planned next-generation galaxy redshift surveys and we make them publicly available as ‘EL-COSMOS’ on the ASPIC data base.

scholarly journals Possible Binary Nature of the Emission-Line Variable Object V 1329 Cygni (= HBV 475)

1977 ◽  
Vol 42 ◽  
pp. 383-385
Author(s):  
Jiři Grygar ◽  
Ladislav Hric ◽  
Drahomír Chochol
Keyword(s):  
Emission Line ◽  
Time Evolution ◽  
Emission Lines ◽  
Type Star ◽  
High Dispersion ◽  
Early Type ◽  
Composite Spectrum ◽  
Binary Nature ◽  
Objective Prism

The peculiar emission-line object V 1329 Cyg was discovered by Kohoutek (1969), who detected in his objective-prism spectrograms an increasing brightness and the presence of emission lines. High dispersion spectra revealed more than 200 emissions of hydrogen, helium, ionized metals and forbidden lines of oxygen, neon, etc. (Crampton et al., 1970; Andrillat, 1970). The object exhibits the composite spectrum of a hot early-type component and a cold M-type star. Its time evolution in a two-colour diagram is seen in Fig. 1.

scholarly journals YZ Cas ± 0.5%

1983 ◽  
Vol 62 ◽  
pp. 108-113
Author(s):  
Claud H. Lacy
Keyword(s):  
Solid State ◽  
Signal To Noise Ratio ◽  
Radial Velocities ◽  
Eclipsing Binaries ◽  
Emission Lines ◽  
Array Detector ◽  
High Dispersion ◽  
Signal To Noise ◽  
Noise Ratio ◽  
M Dwarf

I will discuss one of the results of a continuing program to determine accurate masses and radii of stars in eclipsing binaries. This program actually began in 1976 with my work on the faint M-dwarf system CM Dra (Lacy 1977). By faint I mean . I needed high-dispersion spectra to get radial velocities, and an intensified solid state array detector called the Digicon, which had recently been installed on the coude spectrometer of the 2.7m reflector at McDonald Observatory, turned out to be the answer. 30 minute integrations were sufficient to get accurate radial velocities from the Hγ emission lines. The Digicon is very good at getting crumby spectra of faint objects fast. By crumby, I mean signal-to-noise ratio of less than 100.

scholarly journals The spectral variations of MWC 314

2010 ◽  
Vol 6 (S272) ◽  
pp. 422-423
Author(s):  
Corinne Rossi ◽  
Antonio Frasca ◽  
Ettore Marilli ◽  
Michael Friedjung ◽  
Gérard Muratorio
Keyword(s):  
Emission Line ◽  
Absorption Line ◽  
Radial Velocities ◽  
Line Flux

AbstractNew spectra of MWC314 are presented; they indicate that the V/R emission line flux ratios show signs of varying in an opposite way to the absorption line radial velocities. The latter appear to be due to apparently non-periodic pulsations, perhaps in strange modes.

scholarly journals Gaia-assisted discovery of a detached low-ionisation BAL quasar with very large ejection velocities

2020 ◽  
Vol 634 ◽  
pp. A111 ◽  
Author(s):  
J. P. U. Fynbo ◽  
P. Møller ◽  
K. E. Heintz ◽  
J. N. Burchett ◽  
L. Christensen ◽  
...  
Keyword(s):  
Emission Line ◽  
Absorption Line ◽  
Emission Lines ◽  
Broad Absorption ◽  
Broad Absorption Line ◽  
Red Edge ◽  
First Case ◽  
Bl Lac ◽  
Spatially Extended ◽  
Extended Emission

We report on the discovery of a peculiar broad absorption line (BAL) quasar identified in our Gaia-assisted survey of red quasars. The systemic redshift of this quasar was difficult to establish because of the absence of conspicuous emission lines. Based on deep and broad BAL troughs of at least Si IV, C IV, and Al III, a redshift of z = 2.41 was established under the assumption that the systemic redshift can be inferred from the red edge of the BAL troughs. However, we observe a weak and spatially extended emission line at 4450 Å that is most likely due to Lyman-α emission, which implies a systemic redshift of z = 2.66 if correctly identified. There is also evidence for the onset of Lyman-α forest absorption bluewards of 4450 Å and evidence for Hα emission in the K band consistent with a systemic redshift of z = 2.66. If this redshift is correct, the quasar is an extreme example of a detached low-ionisation BAL quasar. The BALs must originate from material moving with very large velocities ranging from 22 000 km s−1 to 40 000 km s−1. To our knowledge, this is the first case of a systemic-redshift measurement based on extended Lyman-α emission for a BAL quasar. This method could also be useful in cases of sufficiently distant BL Lac quasars without systemic-redshift information.

Sign in / Sign up

Export Citation Format

Share Document