Absolute Spectrophotometry of Wolf-Rayet Stars: Are the Colors the Same?

1982 ◽  
Vol 99 ◽  
pp. 121-125
Author(s):  
Philip Massey
Keyword(s):  
Broad Band ◽  
Emission Lines ◽  
Photoelectric Photometry ◽  
Interference Filters ◽  
One Step

Until now, all that we've known about the magnitudes and colors of Wolf-Rayet stars has been based on photoelectric photometry made with 50–150 A wide interference filters, selected to exclude as far as possible the stronger emission lines (Westerlund 1966; Smith 1968, Lundstrom and Stenholm 1979). This was clearly an improvement on the pioneering efforts of Pyper (1966), who obtained broad band photometry and attempted to correct for the presence of emission; nevertheless, with modern detectors it is possible to go one step further.

scholarly journals Ultraviolet emission line imaging of planetary nebulae with GALEX

2011 ◽  
Vol 7 (S283) ◽  
pp. 308-309 ◽  
Author(s):  
Luciana Bianchi ◽  
Arturo Manchado ◽  
Karl Forster
Keyword(s):  
Galaxy Evolution ◽  
Broad Band ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Continuum Emission ◽  
Ultraviolet Emission ◽  
The Galaxy ◽  
Optical Domain ◽  
Line Imaging ◽  
Shock Fronts

AbstractGALEX (the Galaxy Evolution Explorer) has provided far-UV(1344-1786Å) and near-UV(1771-2831Å) imaging of several Planetary Nebulae (e.g., Bianchi et al. 2008, Bianchi 2012), with flux limits ~27.5 mag/sq.arcsec for objects in the Medium-deph Imaging Survey (MIS). PNe images in the GALEX broad-band UV filters include flux from both nebular line and continuum emission. We use the GALEX grism observing mode to obtain slitless spectral imaging of a sample of PNe with diameters >1′, in the near-UV. We show the first data from this program. The grism produces 2D images of the prominent UV nebular emission lines, when such lines dominate the flux. Combined with monochromatic images of diagnostic lines in the optical domain, such data help detect and interpret ionization and shock fronts, especially in faint nebular regions.

Revisiting the innermost kinematics of M31 galaxy with the OMM Fabry-Perot interferometer

2019 ◽  
Vol 14 (S353) ◽  
pp. 130-133
Author(s):  
Sié Zacharie Kam ◽  
Claude Carignan ◽  
Michel Marcelin ◽  
Philippe Amram ◽  
Jean Koulidiati
Keyword(s):  
Rotation Curve ◽  
Narrow Band ◽  
Optical Emission ◽  
Emission Lines ◽  
Interference Filters ◽  
Andromeda Galaxy ◽  
Fabry Perot ◽  
The Galaxy ◽  
Data Points ◽  
Made In

AbstractWe present observations on optical emission lines acquired with the scanning Fabry-Perot interferometer of the observatoire du Mont Mégantic, of the Andromeda galaxy (M31). A 765 order Fabry-Perot were used with a fast readout EM-CCD. From data obtained, kinematic maps and data points for the rotation curve of the innermost part of the galaxy are derived. Several dozen of regions have been scanned with the Fabry-Perot interferometer and narrow band interference filters. The central 10’x10’ were scanned with five different filters. Observations have been made in order to get better Hα data for kinematics purposes.

scholarly journals One-Step Introduction of Broad-Band Mesoporosity in Silica Particles Using a Stimuli-Responsive Bioderived Glycolipid

2013 ◽  
Vol 2 (3) ◽  
pp. 512-522
Author(s):  
Bejoy Thomas ◽  
Florence Babonneau ◽  
Thibaud Coradin ◽  
Inge N. A. Van Bogaert ◽  
Niki Baccile
Keyword(s):  
Broad Band ◽  
Silica Particles ◽  
Stimuli Responsive ◽  
One Step

scholarly journals New measurements of the cyclotron line energy in Cen X-3

2020 ◽  
Vol 500 (3) ◽  
pp. 3454-3461
Author(s):  
Gunjan Tomar ◽  
Pragati Pradhan ◽  
Biswajit Paul
Keyword(s):  
Broad Band ◽  
Resonant Scattering ◽  
High Energy ◽  
Emission Lines ◽  
Power Law Model ◽  
Pulse Profile ◽  
Line Energy ◽  
X Ray ◽  
Cyclotron Absorption ◽  
Cyclotron Line

ABSTRACT We report results from the analysis of data from two observations of the accreting binary X-ray pulsar Cen X-3 carried out with the broad-band X-ray observatories Suzaku and NuSTAR. The pulse profile is dominated by a broad single peak and show some energy dependence with two additional weak pulse peaks at energies below 15 and 25 keV, respectively. The broad-band X-ray spectrum for 0.8–60.0 keV for Suzaku  and 3.0–60.0 keV for NuSTAR is fitted well with high-energy cut-off power-law model along with soft-excess, multiple iron emission lines and a cyclotron absorption. The cyclotron line energy is found to be $30.29^{+0.68}_{-0.61}$ and $29.22^{+0.28}_{-0.27}$ keV, respectively, in the Suzaku  and NuSTAR  spectra. We make a comparison of these two measurements with four previous measurements of Cyclotron Resonant Scattering Feature (CRSF) in Cen X-3  obtained with Ginga, BeppoSAX,  and RXTE. We find no evidence for a dependence of the CRSF on luminosity. Except for one CRSF measurement with BeppoSAX , the remaining measurements are consistent with a CRSF energy in the range of 29.5–30.0 keV over a luminosity range of 1.1–5.4 × 1037 erg s−1 different from several other sources that show considerable CRSF variation in the same luminosity range.

scholarly journals Multiwavelength consensus of large-scale linear bias

2020 ◽  
Vol 493 (1) ◽  
pp. 747-764 ◽  
Author(s):  
Hengxing Pan ◽  
Danail Obreschkow ◽  
Cullan Howlett ◽  
Claudia del P Lagos ◽  
Pascal J Elahi ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Large Scale ◽  
Broad Band ◽  
Far Infrared ◽  
Absolute Magnitude ◽  
Emission Lines ◽  
Continuum Emission ◽  
Star Forming ◽  
Galaxy Bias ◽  
The Continuum

ABSTRACT We model the large-scale linear galaxy bias bg(x, z) as a function of redshift z and observed absolute magnitude threshold x for broad-band continuum emission from the far-infrared to ultraviolet, as well as for prominent emission lines, such as the H α, H β, Ly a, and [O ii] lines. The modelling relies on the semi-analytic galaxy formation model galform, run on the state-of-the-art N-body simulation surfs with the Planck 2015 cosmology. We find that both the differential bias at observed absolute magnitude x and the cumulative bias for magnitudes brighter than x can be fitted with a five-parameter model: bg(x, z) = a + b(1 + z)e(1 + exp [(x − c)d]). We also find that the bias for the continuum bands follows a very similar form regardless of wavelength due to the mixing of star-forming and quiescent galaxies in a magnitude-limited survey. Differences in bias only become apparent when an additional colour separation is included, which suggest extensions to this work could look at different colours at fixed magnitude limits. We test our fitting formula against observations, finding reasonable agreement with some measurements within 1σ statistical uncertainties, and highlighting areas of improvement. We provide the fitting parameters for various continuum bands, emission lines, and intrinsic galaxy properties, enabling a quick estimation of the linear bias in any typical survey of large-scale structure.

scholarly journals High-Spatial Resolution Observations of Planetary Nebulae

1983 ◽  
Vol 103 ◽  
pp. 507-508
Author(s):  
C. T. Hua ◽  
R. Louise
Keyword(s):  
Spatial Resolution ◽  
Morphological Study ◽  
High Spatial Resolution ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Interference Filters

Monochromatic images in Hα, Hβ, (NII) λ 6584, (SII) λ 6717 and (OIII) λ 5007 lines are presented for morphological study of planetary nebulae. Narrow bandpass (Δλ = 5 to 10 Å) interference filters are generally used in order to discriminate peculiar structures existing in different emission lines. However, large bandwidths (Δλ = 50 Å) along with long exposures, are also necessary in searching for faint nebulosities associated with planetaries.

scholarly journals Photoelectric Photometry of Comet Kohoutek (1973f)

1976 ◽  
Vol 25 (Part1) ◽  
pp. 50-69
Author(s):  
Lubos Kohoutek
Keyword(s):  
Atmospheric Conditions ◽  
Photoelectric Photometry ◽  
Air Mass ◽  
Interference Filters ◽  
European Southern Observatory ◽  
Mean Error ◽  
The Mean

Comet Kohoutek (1973f) has been observed with the 50 cm (f/15) reflecting telescope of the European Southern Observatory, La Silla, Chile, on fourteen nights between January 16 and 30, when the heliocentric and geocentric distances of the comet were r=0 66 - 1 00 A. U and Δ =0 81 - 0.96 A. U. , respectively The 40″ and 80″ diaphragms were used for the photometry of the cometary head (EMI 6256 A photomultiplier) in the UBV system and with six interference filters: CN 3884 Å, CO+ 4267 Å, C2 4737 Å, C2 5172 Å, cont. 5300 Å and Na 5893 Å.The atmospheric conditions were good but the accuracy of our observations was lower than usual due to large extinction (air mass 25 to 43) and twilight. The mean error of one measurement of log F in all but Na 5893 Å filters can be estimated at ±0.02, whereas the accuracy through the Na filter was substantially lower

scholarly journals Modelling the M*–SFR relation at high redshift: untangling factors driving biases in the intrinsic scatter measurement

2021 ◽  
Vol 503 (4) ◽  
pp. 4855-4877
Author(s):  
E Curtis-Lake ◽  
J Chevallard ◽  
S Charlot ◽  
L Sandles
Keyword(s):  
Star Formation ◽  
Time Scales ◽  
Main Sequence ◽  
Broad Band ◽  
Previous History ◽  
Point Sources ◽  
Emission Lines ◽  
Star Formation History ◽  
Medium Band ◽  
Intrinsic Scatter

ABSTRACT We present a method to self-consistently propagate stellar-mass [$\hbox{$\hbox{${\rm M}$}_{\star }$}=\log (\hbox{${\rm M}$}/\hbox{${\rm M}_{\odot }$})$] and star-formation-rate [$\hbox{${\Psi }$}=\log (\hbox{${\psi }$}/\hbox{${\rm M}_{\odot }$}\, {\rm yr}^{-1}$)] uncertainties on to intercept (α), slope (β), and intrinsic-scatter (σ) estimates for a simple model of the main sequence of star-forming galaxies, where $\hbox{${\Psi }$}= \alpha + \beta \hbox{$\hbox{${\rm M}$}_{\star }$}+ \mathcal {N}(0,\sigma)$. To test this method and compare it with other published methods, we construct mock photometric samples of galaxies at z ∼ 5 based on idealized models combined with broad- and medium-band filters at wavelengths 0.8–5 μm. Adopting simple Ψ estimates based on dust-corrected ultraviolet luminosity can underestimate σ. We find that broad-band fluxes alone cannot constrain the contribution from emission lines, implying that strong priors on the emission-line contribution are required if no medium-band constraints are available. Therefore, at high redshifts, where emission lines contribute a higher fraction of the broad-band flux, photometric fitting is sensitive to Ψ variations on short (∼10 Myr) time-scales. Priors on age imposed with a constant (or rising) star formation history (SFH) do not allow one to investigate a possible dependence of σ on $\hbox{${\rm M}$}_{\star }$ at high redshifts. Delayed exponential SFHs have less constrained priors, but do not account for Ψ variations on short time-scales, a problem if σ increases due to stochasticity of star formation. A simple SFH with current star formation decoupled from the previous history is appropriate. We show that, for simple exposure-time calculations assuming point sources, with low levels of dust, we should be able to obtain unbiased estimates of the main sequence down to $\mathrm{ log}(\hbox{${\rm M}$}/\hbox{${\rm M}_{\odot }$})\sim 8$ at z ∼ 5 with the James Webb Space Telescope while allowing for stochasticity of star formation.

scholarly journals New structural and spectroscopic data for eosphorite

1993 ◽  
Vol 57 (387) ◽  
pp. 329-336 ◽  
Author(s):  
M. A. Hoyos ◽  
T. Calderon ◽  
I. Vergara ◽  
J. Garcia-Solé
Keyword(s):  
Crystal Structure ◽  
Optical Absorption ◽  
Excitation Spectrum ◽  
Spectroscopic Data ◽  
Broad Band ◽  
Emission Lines ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

AbstractX-ray diffraction refinement of the crystal structure of eosphorite has been carried out with reference to the orthorhombic space group Cmca. The structure is similar to that previously described by Hanson (1960), but the standard deviations are improved. Optical absorption and photoluminescence have also been studied for this mineral. Two sharp emission lines, denoted as R1 and R2, superimposed to a broad band (630-750 nm) have been related to the presence of Cr3+ ions. The excitation spectrum of these emissions confirms that the absorption (excitation) bands centred at 431 nm and 585 are related to with 4A2 → 4T1 and 4A2 → 4T2 spin allowed transitions of this ion.

scholarly journals First Results of Optical Monitoring of 3C 390.3

1997 ◽  
Vol 159 ◽  
pp. 163-164
Author(s):  
M. Dietrich ◽  
P.T. O’Brien ◽  
K. M. Leighly
Keyword(s):  
Time Scales ◽  
Broad Band ◽  
Emission Lines ◽  
High Temporal Resolution ◽  
Line Profiles ◽  
X Ray ◽  
First Results ◽  
Long Time ◽  
Flux Measurements ◽  
Calar Alto

In late autumn 1994, the International AGN Watch started a multiwavelength monitoring campaign on 3C 390.3, the first radio-loud AGN to be selected for high temporal-resolution monitoring from the radio domain to X-ray energies. This AGN is is of particular interest since significant variations have been observed on both short and long time scales in both the line fluxes and line profiles (Barr et al. 1980, Veilleux & Zheng 1991).In the optical, spectroscopic data and broad-band flux measurements in B, V, R, and I were obtained. The brightness of 3C 390.3 was calculated relative to the stars in the field. The R magnitudes are based on observations recorded at Calar Alto, Spain, in 1994 December. Generally, AGN spectra are intercalibrated using narrow forbidden emission lines since these lines can be taken as constant on time scales of decades (Peterson 1993). Since the [O III] λλ4959, 5007 flux is variable on time scales of several months (Zheng et al. 1995), these lines were studied in detail. We found that they were constant within ~2% during 1995 (Dietrich et al. 1996). The spectra were therefore intercalibrated by using the narrow forbidden emission lines. 3C 390.3 was also observed with IUE for 14 months (O’Brien et al. 1996) and with ROSAT for nine months in 1995 (Leighly et al. 1996). Radio data were also obtained during a 3-month MERLIN campaign.

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