IPHAS: the INT H-alpha emission survey

IPHAS is an on-going imaging survey in H alpha covering the northern Galactic plane. Below are some example images, made by mosaicing the individual frames. More information is available from the survey pages.

Simeiz 22

The images show the nebula Simeiz 22 (RA 01 30 25, DEC +58 26, J2000). The object is classified as an old planetery nebula, but has been suggested to be an HII region or a supernova remnant. There is no other HII region nearby. Napiwotzki (1999: AA 350) analyzed a hot white dwarf star with a temperature of 105K, which could be the central star of a planetary nebula, and a derives a distance of 965 pc. This would give a diameter of almost 3 parsec. The structure is far more filamentary than is normally seen in planetary nebulae. The bright edge is due to interaction with the interstellar medium. The radio flux is 40 mJy (Condon et al).
[ Simeiz 22 ]
The INT survey shows the nebula to be twice as large as listed in the Strasbourg-ESO catalog of Galactic Planetary Nebulae: 10 arcminutes instead of 6. At the faintest levels the shell can be seen to be closed, but it is much brighter on the South Eastern side. A small, faint, edge-on galaxy can be seen in the SW corner of the image on the right. This galaxy (RA 01:29:10.2, DEC +58:20:02 (J2000)) is also an IRAS source. [ Simeiz 22 ]

S147

[ S147 ] This is a continuum subtracted Hα image of the supernova remnant S147, located on the sky toward the anti-galactic centre. A strength of IPHAS is that it offers the chance to construct images of parts of the Galactic Plane on any scale from arcseconds up to degrees. This is a very large-scale image, built up by mosaicking a large number of overlapping IPHAS fields together: the total imaged area is roughly 5 x 3.5 square degrees. The bright blob to the left of the picture is a more typically compact Galactic nebula. (credits: Albert Zijlstra, University of Manchester and Jonathan Irwin, IoA Cambridge)

G084.9-01.2: the North America nebula

A filamentary HII region is seen in this image, which is about 1.5 degree across. The HII region is centered on RA 20 59 42, DEC +43 35 (J2000). The nebula is the 'Mexico' part of the North America nebula, which extends several degrees further to the north. To the west, outside the frame, is the Pelican nebula. [ G084.9-01.2 ]
[ G084.9-01.2 ] [ G084.9-01.2 ]
Using different cuts for the colour encoding, a molecular cloud (the 'Gulf of Mexico') shows up black against the surrounding H alpha emission. A detail of the larger image shows the small, dusty condensation compressed by radiation or wind coming from the dark cloud.

IRAS01342+6358 / 6351

[ IRAS01342+6358 ] This object is a newly discovered HII region in the outer galaxy (Temporin & Weinberger 2004). The image below is almost 1 degree across: it shows the extended nebulosity, with the embedded bright condensations showing the most recent star formation. The structure is reminiscent of the much closer object W4.
The cluster near the top of the frame is NGC 609, an essentially unstudied cluster--perhaps because its simbad position is wrong by 7 arcminutes. There is no known relation between the HII region and the cluster.