Abstract
We have imaged fields of total area 189 arcmin2within 1° of the Galactic centre in narrow band L (~3.6µm) using UKIRT, with major-axis fields at l = ±1° and minor-axis fields at b = +0.4° and b =–1°.
Differential number counts show a marked asymmetry between at +ve and –ve longitude, with the counts at l =–1° being greater by a factor of ~1.6. We also find that for the two minor axis fields, number counts are nearly the same, despite the expected steep drop-off in numbers between |b|=0.4° and |b|=1.0° However, both these effects could be due to different amounts of extinction of order Δ Av 12. In addition, the b = –1° and l = 1° fields show a clear faint excess number count compared with the other fields, plausibly due to holes in the extinction.
On comparison of the L-band data with DENIS protosurvey K-band data, we deduce that the extinction Av varies between 5 and 40 on a scale of just arcminutes near 1 = –1° consistent with the known presence of large molecular clouds. The size of this effect suggests that the major contribution to observed asymmetries may be an extinction effect rather than a structural, possibly bar-like asymmetry.
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References
Catchpole, R. M., Whitelock, P. A., & Glass, I. S. 1990, MNRAS, 247, 479
King, I. R. 1989, in The Milky Way as a Galaxy, ed. Gilmore, G., King, & I. R.,VanderKruit, P., 49
Liszt, H. (1988), in Galactic and Extragalactic Radio Astronomy, ed. G. L. Verschuur, G. L., & K. I. Kellermann (Springer), 360
Mathis, J. S. 1990, ARA&A, 28, 37
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© 1997 Springer Science+Business Media Dordrecht
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Unavane, M., Gilmore, G. (1997). The Galactic Central Regions at 3.6 µM . In: Garzón, F., Epchtein, N., Omont, A., Burton, B., Persi, P. (eds) The Impact of Large Scale Near-IR Sky Surveys. Astrophysics and Space Science Library, vol 210. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-5784-1_12
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DOI: https://doi.org/10.1007/978-94-011-5784-1_12
Publisher Name: Springer, Dordrecht
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