There are times when a celestial object does not surrender its secrets to those peering eyes of the astronomers at Chiefland. One such object that has maintained its privacy is ultraluminous x-ray object NGC 5474-X1 within dwarf galaxy NGC 5474 in Ursa Major. The attached images of pathologic galaxy NGC 5474, which is warped by nearby M101, show exuberant star formation as evidenced by lots of HII regions in contorted blue star arms. Compare my 9-hour LRGB image to a deep image taken with the 4-meter scope on Kitt Peak (attached mosaic). A link to an amazing close-up Hubble image is below. This 4.7 arcmin galaxy, however, is refusing to give up the optical location of its ultraluminous x-ray source (NGC 5474-X1) identified by the Chandra x-ray telescope. But I should not feel so bad. Even the Hubble Space Telescope couldn’t find it optically! That didn’t stop me from trying! Maybe I’ll next attempt to violate the optical counterpart of NGC 7319-X4.
P.S. – The attached widefield monochrome “scout” image shows positions of M101 and NGC 5474; 1 minute Lum exposure with 100mm f/3.8 Vixen refractor and SBIG 11K camera
P.S.2 – Close-up image of NGC 5474 taken with 14.5-inch RCOS and Apogee camera: 6 hrs LUM 1×1; 3 hours RGB 2×2 – not much RGB data / may get more this fall
http://mnras.oxfordjournals.org/content/424/2/1563.full.pdf — Great article on the ULX in NGC 5474 – be patient – takes a while to load pdf
http://www.nasa.gov/content/goddard/hubble-sees-a-dwarf-galaxy-shaped-by-a-grand-design — Hubble Eye Candy
https://www.noao.edu/image_gallery/html/im1063.html — NOAO website with Kitt Peak image