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Dust in edge-on spiral galaxies from the J-band of the 2MASS Large Galaxy Atlas. Angelos Misiriotis (1) and Manolis Xilouris (2). (1) University of Crete, Department of physics (2) National observatory of Athens. Motivation (a case for “optical” detection of dust).
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Dust in edge-on spiral galaxies from the J-band of the 2MASS Large Galaxy Atlas Angelos Misiriotis (1) and Manolis Xilouris (2) (1) University of Crete, Department of physics (2) National observatory of Athens
Motivation (a case for “optical” detection of dust) • Optical studies are coplementary to FIR observations • Require less exotic equipment • Take advantage of huge archaives • Constrain the emissivity
Why edge-on ? Image from the 2MASS L.G.A. Jarrett T. H., Chester T., Cutri, R. Schneider, S. E. Huchra, J. P., 2003, AJ, 125, 525
Why J-band ? • In the J Band (τ ~ 0.1) • The edge-on line of sight reaches the center • The dust lane is still visible Figure from: Bosma A., Byun Y., Freeman K. C. Athanassoula E., 1992, ApJ, 400, 21
Why the 2MASS, Large Galaxy Atlas(*)? • Large homogenious sample • Easily available • Good pilot before spending months for deeper observations Out of the LGA 28 edge-on galaxies were selected for this study. (*)Jarrett, T. H.; Chester, T.; Cutri, R.; Schneider, S. E.; Huchra, J. P., 2003AJ....125..525J
The Model • A stellar bulge (de Vaucoulers) Xilouris E. M., Byun Y. I., Kylafis N. D., Paleologou E. V., Papamastorakis, J., 1999, A&A, 344, 868
The Model • A stellar bulge (de Vaucoulers) • A stellar exponential disk Xilouris E. M., Byun Y. I., Kylafis N. D., Paleologou E. V., Papamastorakis, J., 1999, A&A, 344, 868
The Model • A stellar bulge (de Vaucoulers) • A stellar exponential disk • An exponential dust disk Xilouris E. M., Byun Y. I., Kylafis N. D., Paleologou E. V., Papamastorakis, J., 1999, A&A, 344, 868
Textbook Cases (7/28 galaxies ) Observation Model
Passable Cases (8/28 galaxies )
Impossible Cases (5+8/28) Which leaves us with 15/28 galaxies to draw some results on the dust properties.
Results Optical depth as a function of MK
Results Optical depth as a function of dust mass
Conclusions J-Band is ideal for optical studies of dust in edge-on galaxies provided a high resolution. Larger spirals exhibit higher face-on optical depth. There might be a threshold of the optical depth in normal spiral galaxies.