Atlas Image mosaic,
covering 8.0´ × 8.0´ on the sky, of the star
LkH 221, a probable pre-main-sequence
emission-line (T Tauri) star (Weintraub
1990, ApJS, 74, 575). Image mosaic by S. Van Dyk (IPAC).
Atlas Image mosaic,
covering 11.0´ × 11.0´ on the sky, of the spiral galaxy
NGC 4565. This galaxy, much like other nearby, large edge-on spirals,
such as NGC 5907 and
NGC 891, resemble our Milky Way as
it would be seen edge-on from a distance.
Motivated by a flat rotation curve, implying a total mass of
dark matter of 3.5×1011 M,
Beichman et al. (1999, ApJ, 523, 559), based on deep Infrared Space
Observatory ISOCAM observations at 4.5 µm, find that the faint
galactic halo likely does not consist of late-M dwarfs distributed spherically,
but could not exclude the presence of lower-luminosity brown dwarf stars.
Image mosaic by S. Van Dyk (IPAC).
Atlas Image mosaic, covering 6.0´ × 6.0´ on the sky, of the southern HII, or ionized hydrogen, region RCW 46. This region lies at the eastern edge of a recently-discovered large neutral hydrogen supershell, or giant void, with radius 300 pc (980 light years; McClure-Griffiths et al. 2000, AJ, 119, 2828). The supershell is in an interarm region near the Carina spiral arm in the Milky Way, and the presence of molecular gas and HII regions along the supershell indicate that star formation may have been initiated by the supershell's expansion. Image mosaic by S. Van Dyk (IPAC).