Discoveries and Current Projects with the AAO/UKST H-alpha Survey

A rich new vein of Galactic Planetary Nebulae

New Herbig-Haro Objects in Orion

New probable SuperNovae

A rich new vein of resolved/extended Galactic Planetary Nebulae

As an example of the impact this survey can have for our study of the galaxy we present in the figure below four examples of new, resolved/extended Planetary Nebulae (PNe). They were discovered by one of us (QAP) from simple visual scrutiny of some of the first 3 hour H-alpha exposures taken on standard 5-degree field centres. They were confirmed as new discoveries by cross-checking with SIMBAD and the on-line version of the Strasbourg-ESO catalogue of Planetary Nebulae (Acker et al. 1992) and a hardcopy of the 1996 Acker PNe supplement (not yet on-line).

These new PNe are invisible or ocassionally barely detectable on previous deep standard UKST R or J-band exposures of the field but are easily found on the new H-alpha exposures.

Follow-up visual searches of 24 new 3 hour H-alpha exposures by Q.Parker and M.Hartley have found about 100 new PNe candidates

None of these are in the existing Acker 1992, 1996 catalogues. So far every candidate followed up with CCD imaging (6 so far) has turned out to be a real object.

If this frequency is replicated throughout the survey then about 1000 new optically detected resolved PNe should be discovered.

This can be compared with the ~1500 currently know in the galaxy (both hemispheres) based on entries in the on-line Acker Strasbourg-ESO catalogue and the 1996 Acker supplement. Simple visual scanning of the survey films is thus expected to significantly increase the numbers of faint, extended Southern Galactic plane PNe. These low surface brightness PNe have proved ellusive to many previous photographic or objective-prism searches.

Here we expect to tap a rich new vein of these evolved objects.

Follow-up spectroscopy is planned to confirm the nature of many of these new PNe candidates as well as the host stars which are expected to be in the white dwarf phase of stellar evolution. Due to their anticipated sheer numbers, the importance of this new source of PNe for studies of stellar evolution, PNe morphology, interaction and dissipation with the ISM and for galactic kinematics cannot be overstated.

Planned SuperCOSMOS scans of these films would undoubtedly pick-up many more unresolved or barely resolved candidates for further study via comparison with the equivalent `continuum' short-red exposures which have similar (slightly shallower) depth.

Figure 1. Examples of four new resolved Planetary Nebulae

These PNe were all discovered from new 3-hour H-alpha exposures taken on standard 5-degree field centres. Each image is 2.6 x 2.6 arcminutes in size.

Figure 1a & b. Top left & top right are both from exposure HA17614 (field 334)

Figure 1c & d. bottom left from exposures HA17617 (field 226) & bottom right from exposure HA17619 (field 392).

Figure 2a. Gives a further new PNe discovery taken on one of the new 4-degree field centres (exposure HA17702, field 1063H 19h12m, -12deg B1950).

The image is about 2.6 x 2.6 arcminutes in size.

Figure 2b gives a follow-up discovery confirmation image.

This was taken with the Taurus Tunable Filter (TTF) on the AAT on Nov.6th by Brian Boyle and Steve Lee.

The image is a colour composite formed from 3 seperate 500sec exposures centred on the H-alpha, [NII] and [SII] regions (Red:Green:Blue). The planetary nebulae is confirmed giving confidence in the veracity of our visual search criteria on the original AAO/UKST H-alpha films. The [SII] was quite weak and contributes little to the image. Note that the composite depth of this AAT CCD image is comparable to the UKST H-alpha 3-hour exposure.

New Herbig-Haro objects in Orion

Simple visual scrutiny of the first deep H-alpha film of the Orion complex taken for an associated project by consortium members led by Mike Masheder at Bristol has also revealed several new Herbig-Haro objects. After initial discovery by QAP, Bill Zealey, Stacy Mader and QAP performed independent scans of this film and found 20 new H-alpha emission line nebulosities and improved detail in a further 4 previously known objects, Mader et al (MNRAS, submitted). Clearly the potential for further such discoveries in active star forming regions is high.

We show in figure below the H-alpha image of V510 Ori (= HBC 177) taken from the new Orion film. The image clearly shows the start to possess a highly collimated jet and a bow shock 2arcminutes to the ENE.

New H-alpha image of a Herbig-Haro object and jet taken from the new Orion film. The image, which is about 4x3 arcminutes across, clearly shows the well defined jet and bow-shock.

We also present an annotated scanned H-alpha image of a larger region in the Orion complex showing a candidate giant HH flow. The northern HH objects (HH 306B to HH 309A) are shown in relation to L1641-N (marked by a cross) and the optical sources PR Ori and V832 Ori. The 3pc flow HH 34 is seen to the west with its terminal redshifted (HH 33/40) and blueshifted (HH 88) shocks. The central source is indicated as HH34*. North is up and east is left. The image size is 35x50 arcmin. The image is courtesy of S.Mader.

New probable SuperNovae remnants

Several new probable supernovae remants have also been discovered including the example below. The image is about 1-degree on a side and was found by QAP from visual scans of a 3 hour H-alpha exposure.

Further updates, discoveries etc will be placed on these pages on a regular basis. It may be decided to keep a running inventory of all new PNe discoveries together with images and co-ordinates.

Please note that the scanned images do not reflect the image quality of the original UKST H-alpha films.

Refer to main H-alpha AAO/UKST survey pages HERE

Pages maintained by Quentin A Parker (qap@roe.ac.uk). Last revision: 19th March 2000