cataloging and imaging unexplored nebulae of the Milky Way Galaxy.
Click on image for larger view.
One of the discoveries made while imaging the Integrated Flux Nebulae* complex near M81-82.
Flux Nebulae is the term coined to describe a nebula illuminated by the
integrated visual and UV flux of the Milky Way.
This distinguishes this type of nebula from the typical Reflection Nebula, which is illuminated by a nearby star.
Unexplored Nebulae Project
by Steve Mandel
What I Found
The UNP began in December of 2004 when I noticed a huge nebula complex around the galaxies M81-82. It is an area of the sky where one does not expect to see many nebulae due to its high northerly galactic latitude. I was taking an image of the galaxies using my remotely controlled telescope located in the mountains of Southern New Mexico at New Mexico Skies. I noticed a "smudge" on the image which upon closer examination turned out to be a huge, generally unknown, nebula complex. I was puzzled and astounded - I had never heard of any nebulosity so far above the galactic plane or in the vicinity of M81-82. I looked in the standard atlases and reference guides and found nothing.
After consulting with radio and optical astronomers both in the US, Australia and the UK (most of whom had no idea what it was), it was determined that I had come across a portion of a huge but little-known dust complex. It was originally seen on Palomar Sky Survey plates in the mid-60s. Similar clouds were then found on plates shot from the UK Schmidt at Siding Spring Observatory in Australia. David Malin found evidence of these high-latitude dust clouds on 35 of the 900 plates shot from Siding Spring. The clouds shot from Palomar were catalogued by B.T. Lynds in 1965, and descriptions of a couple of these nebulae were written about by Allan Sandage in 1976.
Sandage and others noted the dust component of these nebulae but did not know about the Extended Red Emission (ERE), a broad-banned red signal (600-1000 nanometers) generated by some of dust particles. The suspect emitting dust particles are known as Polycyclic Aromatic Hydrocarbons (PAH), a common component of galactic dust. In some cases the ERE can account for 30% of the light being emitted from these clouds. It is now also known that, in addition to scattering blue light and luminescing in the red (ERE), the dust in these clouds are luminescing in the blue, also.
In the late 90's, data from two satellites with FIR (Far Infrared) sensors (100-250 micron range), IRAS and DIRBE, were assembled into an "all-sky" dust map finally revealing the extent of this nebulosity. Dust is a major component of the Interstellar Medium (ISM) in the Milky Way Galaxy and these nebulae show and the high latitudes are no exception. These maps were assembled to help astronomers measure the amount of light extinction and "reddening" caused by interference from the dust particles at high galactic latitudes. Blue light is scattered by the dust so the color of the light shifts towards the red (this is not to be confused with red-shift caused by a receding energy source). The maps allow astronomers to take this dust interference into account when gathering data from extra-galactic sources. While diffuse in most places, they are not uniform and in some areas form thick pockets, clouds, waves and other discernible structures (nebulae) that can be catalogued, mapped and imaged.
Up until now these dust clouds have been thought of as a nuisance by most astronomers. Think of photographing something through a dirty window - this high galactic latitude dust is analogous to the dirt on that window if you are trying to image a distant galaxy. Except, now we know that the "dirt" itself is worthy of study and beautiful to behold.
What They Are
Amazingly, the giant dust clouds that I came across were high above the plane of the Milky Way, many around the North Galactic Pole and Polaris. Similar clouds exist around the Southern Galactic Pole. Both are unique in that they do not reflect, scatter or fluoresce due to the radiation of any individual star or cluster of stars, the way most nebulae we know about do. Rather, these large, high-latitude nebulae are reflecting and being ionized by the integrated flux of all the stars in the Milky Way Galaxy! Their estimated distance from the galactic plane is ~100 pc.
None of these unique individual nebulae have ever been fully documented, mapped or photographed until now. I have labeled these nebula Integrated Flux Nebula (IFN). Based on the very low-resolution extinction dust maps prepared by astronomers Dr. David Schlegel of Lawrence Berkeley Labs and Dr. Doug Finkbinder of Harvard University (who were kind enough to spend time with me and help me understand the data), I identified a number of possible unknown nebulae complexes to explore. I have catalogued and imaged a number of these new structures. One, labeled MW2 in our catalogue and called The Angel Nebula, is shown at the top of this page. I will continue to explore regions that show promise of revealing even more of these complex and beautiful IF Nebula. You can see other images on the Integrated Flux Nebula page. I will be updating the catalog of these objects as I find them and posting them on the web page, Mandel-Wilson Catalog of Unexplored Nebulae.
To learn more about the physics of IF Nebula, I contacted the Dusty Astronomical Systems Group of the Ritter Astrophysical Research Center, headed by Dr. Adolf Witt. They were very pleased to see some photos of the dust clouds that revealed both the reflection and emission features (ERE), and they asked me to collaborate with them on dust cloud research. Currently, we have a proposal in to the National Science Foundation for a set of 15 Windhorst filters covering from 3370 angstroms to 9730 angstroms. I will use the filters to help gather data on dust cloud morphology. These filters are designed to gather data at very specific wavelengths to avoid major night sky emission lines/bands, allowing the camera to record extremely faint light from the nebulae. Until we are able to obtain that set of filters, we will be using AstroDon filters, both broadband and near IR, to measure for ERE in various high-latitude clouds.
While investigating these IF Nebula, I met astronomers Dr. Matt Haffner and Dr. Ron Reynolds, both from the University of Wisconsin - Madison. They introduced me to WHAM, the Wisconsin H-Alpha Mapper. Their research is focused on the nature of the gas, ionized Hydrogen (HII), in the ISM. They have identified a number of H-alpha point sources that have not previously been imaged with anything less than a 1-degree beam via the WHAM instrument. I am working with them to obtain higher resolution images of many of these objects using narrow-band filters, primarily H-alpha filters. While looking at one of these sources, I discovered what I call The Horns of Vega - two horn-like structures seemingly emanating from Vega. The image can be see on the Emission Nebula page of this web site. They are actually faint H-a shock fronts that are line-of-sight with Vega. We are also working on identifying WHAM data points that have no identifiable ionization source but lie within the plane of the Milky Way where sources are plentiful. We plan to use the WIYN .9m telescope on Kitt Peak to gather higher resolution images of some of these regions and then publish the results in professional journals.
On this web site, you will find the beginnings of the Mandel-Wilson (MW) Catalogue of Unknown Nebulae, images of both the integrated flux and emission nebulae that I have been working on, and information on the equipment used to capture the images. We call these nebulae "unknown" because they have not previously been imaged or well-studied. If you would like to contribute images or help with the research on any of these objects, please contact me.
This has been, and continues to be, a very exciting project, filled with the thrill of exploration and discoveries. I hope you enjoy this web site. Please contact me if you have any questions or comments: Email: Steve Mandel.
Acknowledgment and Thanks
Generous support from a number of people and companies has made this project possible. I thank them for their faith in me and for their belief in supporting scientific research, albeit by an amateur.
First, thanks to the major project sponsor, Michael Wilson (who the catalog is co-named for), founder of the Tzec Maun Foundation, for his very generous support. This project would not have been possible without his help. I also want to thank the other important sponsors of this project: Santa Barbara Instrument Group for the loan of CCD cameras, Mike and Lynn Rice of New Mexico Skies for their help in setting up and maintaining equipment, Don Goldman, AstroDon Filters, for the loan of his filters and Brad Ehrhorn of RC Optical Systems for the use of his wonderful telescopes. They all helped make this project a reality.
I would like to thank Dr. Adolf Witt of the Dusty Astrophysical Research Group who has been very helpful and pointed me towards some exciting research in this area and has become my "dust mentor" and friend. Also, many thanks to Dr. Matt Haffner and Dr. Ron Reynolds for their time, support and help with the project. Many thanks also to Dr. David Schlegal and Dr. Doug Finkbinder for taking the time to explain their dust data to me. In addition, I would like to thank David Malin for his information on the UK Schmidt plates and for sharing his thoughts on high-latitude galactic dust clouds in the Southern Hemisphere with me.
addition, a number of friends helped with gathering images, the loan of
time on their telescopes, and processing help and advice: Ken Crawford,
Don Goldman, Rob Gendler, Russ Croman, Jim Misti and the SSRO
guys. Thanks guys! And, my eternal love and gratitude to my
family for their patience and understanding of my passion for imaging the
photographs, unless otherwise noted, copyright, ©2005, by Steve Mandel.
Images may not be downloaded or used without the consent of the photographer.