New trends in CCD photometry of galaxies

1985 ◽  
pp. 1-12
Author(s):  
B. Fort
Keyword(s):  
Ccd Photometry

scholarly journals CCD photometry and spectroscopy of 14 IRAS sources having far-IR colours similar to Planetary Nebulae

1997 ◽  
Vol 180 ◽  
pp. 365-365
Author(s):  
B. E. Reddy ◽  
M. Parthasarathy
Keyword(s):  
Spectral Energy Distribution ◽  
Planetary Nebulae ◽  
Spectral Energy ◽  
Galactic Latitude ◽  
Ccd Photometry ◽  
Ccd Imaging ◽  
Evolved Stars ◽  
Molecular Features ◽  
Intense Mass ◽  
Low Mass

CCD imaging and BVRI photometry of 14 IRAS sources with far-IR colours similar to planetary nebulae and post-AGB stars are presented. Also results of optical and near-IR spectroscopy of 10 of these candidates are given. Based on the spectral energy distribution from 0.4 μm to 100 μm, the sample of program stars are put into two groups. The sources IRAS 08187-1905, IRAS 05238-0626 and IRAS 17086-2403 present similar flux distributions. These three sources have detached cold dust components with dust radii Rd ≈ 1000 R∗. The low infrared variability of theses sources suggests that the intense mass loss has been ceased. All three sources are at high galactic latitude (1>9°) suggesting that these are old low-mass evolved stars. In the IRAS colour-colour diagram of Likkel et al (1991) these sources fall in the region where most of the stars are evolved stars and PNe but without CO detection. This is consistent with at least one source IRAS 17086-2403, in which OH and CO molecular features are not detected. The far-IR excess, non-variability and high latitude of these objects suggest that these are post-AGB supergiants, slowly evolving towards planetary nebula phase.

CCD Photometry and Optical Variability of Gamma-Ray-loud BL Lacertae Object OJ 287 in a Low, Fainter State

2007 ◽  
Vol 133 (5) ◽  
pp. 1995-2000 ◽  
Author(s):  
X. Zhang ◽  
G. Zhao ◽  
Y. G. Zheng ◽  
L. Ma ◽  
Z. H. Xie ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Optical Variability ◽  
Ccd Photometry ◽  
Bl Lacertae

scholarly journals The Observatorio Astronómico Nacional - Tonantzintla: Site Evaluation

2009 ◽  
Vol 5 (S260) ◽  
Author(s):  
H.M. Hernández-Toledo ◽  
L.A. Martínez-Vázquez ◽  
A. Pani-Cielo
Keyword(s):  
Ccd Photometry ◽  
Local Conditions ◽  
Astronomy Education ◽  
Site Evaluation ◽  
New Instrumentation ◽  
Sky Conditions ◽  
Alternative Solutions ◽  
Term Monitoring

AbstractThe objective of this contribution is to present some results of an evaluation on the local conditions at the site that were considered in order to propose that the Observatorio Astronómico Nacional, Tonantzintla, (OAN-Tonantzintla) become a National Facility for Astronomy Education. The evaluation included a quantitative diagnostic (CCD photometry) on the quality of the local sky. The attributes of the 1-m telescope, the current instrumentation and a well planned upgrading that includes new instrumentation is considered at the basis for a successful transition maintaining the attractiveness of the site for astronomy education. A 3-year upgrading program actually in progress at UNAM is providing funding for that purpose. Physics and astronomy programs at college and graduated levels at UNAM will benefit from this, yielding clear connections among astronomy researchers and educators and students at various levels. Although the OAN-Tonantzintla faces the danger of deteriorating its sky conditions, we are maintaining awareness of the night sky characteristics in long-term monitoring campaigns and encouraging the local authorities to find alternative solutions to this problem.

BVRI CCD-Photometry of comparison stars in the fields of galaxies with active nuclei. V

Astrophysics ◽  
2013 ◽  
Vol 56 (3) ◽  
pp. 343-358 ◽  
Author(s):  
V. T. Doroshenko ◽  
S. G. Sergeev ◽  
Yu. S. Efimov ◽  
G. A. Borman ◽  
D. N. Okhmat ◽  
...  
Keyword(s):  
Ccd Photometry ◽  
Comparison Stars
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