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3D Distance Vectors and Imaging of Interacting Galaxies NGC 4088 and NGC 4085

This study presents a detailed analysis and mosaic imaging of the interacting galaxies NGC 4088 and NGC 4085 in the Ursa Major constellation. We explore their characteristics, calculate the 3D distance vectors between the two galaxies, and discuss the challenges faced during image collection and processing. By combining multiple images taken during a night of observation, we provide a final enhanced mosaic that reveals the unique structure of these galaxies. The methodology includes image calibration, background matching, and distance measurement techniques.

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3D Distance Vectors and Imaging of Interacting Galaxies NGC 4088 and NGC 4085

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  1. North: up East: Left Mosaic Imaging and 3D Distance Vectors NGC 4088 and NGC 4085 – Interacting Galaxies Chelsea Braun Image: Digitized Sky Survey

  2. North: up East: Left Outline • Introduction • Theory • Mosaic Image Plan • Creating the Images • Final Image • Distance Calculation • Discussion Image: Jeff Johnson, croppedhttp://jeffjastro.com/dso/NGC4088_30Jan09.htm

  3. North: up East: Left Introduction • NGC 4088 is a weakly barred spiral galaxy with morphological type SAB(rs)bc • NGC 4085 is an Sc D galaxy • Found in the Ursa Major constellation • Part of the M109 group Image: Stellarium Credit: Simbad

  4. Theory • The 3D distance vector • Calculating the distance between 2 galaxies • Not as simple as finding the distance in arc seconds on an image and then converting to parsecs • Requires knowing the distance to these objects

  5. Geometry

  6. Distance • 4 equations • Where the distance to the galaxies, d1 and d2, can be determined using arcmins, is determined from the image with scale, S

  7. Imaging • Spent a night collecting 1hr 30mins of data • 30 mins for 3 7’x7’ images • Difficulties? • Telescope moved a lot • Provided difficulties when combining the images

  8. North: up East: Left Mosaic Image Plan • Take three 7’x7’ images, 30 mins at 60sec exposures • North up and East right (for all images) • Have common stars in each image to line up the images NGC 4088 MID NGC 4085 Image: Digitized Sky Survey

  9. North: up East: Left Mosaic Image Plan 15’x7’ Image: Digitized Sky Survey

  10. North: up East: Left NGC 4088 • 30 images at 60sec exposures, 7’x7’ image • Calibrated the images • Broke into 2 subgroups: 1-9, 10-30

  11. North: up East: Left NGC 4088

  12. North: up East: Left NGC 4088 • Final NGC 4088 image • Combine the final averaged images from the substacks into 1 stack • Register them • Combine

  13. North: up East: Left NGC 4088 Image: 6.7’x5.2’

  14. MID • 30 images at 60 second exposures, 7’x7’ images • The middle star image had the most difficulties • Most noise • First 5 frames removed (guide stars missing) • Broken down into 3 substacks: • Substack 1: 6-15 • Substack 2:16-21 • Substack 3: 22-30

  15. Substack 1 • Most difficult to register • done for the 10 frames using TurboReg: scaled rotation • Pick 2 points on 2 different images • Aligns those 2 points using translation and rotation • Rotation is a bad thing

  16. North: up East: Left Substack 1 Slide 15 Slide 6

  17. Substack 1 • Crop all the manually registered images and place in a stack • PROBLEM: slight rotation in the TurboRegplugin caused a very noisy averaged image

  18. North: up East: Left Substack 1

  19. North: up East: Left Substack 1

  20. North: up East: Left Substack 2 & 3 Final Images

  21. North: up East: Left Mid – Final Image Image: 6.5’ x 5.5’

  22. NGC 4085 • 30 images at 60 second exposures, 7’x7’ • No substacks needed • Although 2 registrations were necessary to align the images

  23. Image: 6.7’x5.8’ NGC 4085 – Final Image North: up East: Left

  24. Background Levels • Background levels were matched to create the mosaic • Measured the background levels of the 3 final images • Took the darkest background level and matched them into the other images • Subtracted the differences in background levels

  25. North: up East: Left

  26. Background Levels • Convert to 16 bit to use MosaicJ • Find the minimum and maximum pixel values for all three images and set the B & C min and max to these values over all 3 images • Then convert to 16 bit

  27. North: up East: Left Final Image Image: 16.8’ x 7.6’

  28. Distance Between Galaxies • Measured a distance of 894.79 pixels between galaxies

  29. Distance Between Galaxies • Using the 4 equations • Darcmins= 12.2' ± 0.4' • Drads = 0.0035 ± 0.0001 • Dparsecs = 0.043 ± 0.001 Mpc • d1-d2 = 0.33 Mpc • D' = 0.33 ± 0.03 Mpc

  30. Discussion • Fixing the MID image • Save a ROI line between stars for substack 1 and use the same length distance • Should eliminate rotation?

  31. END • THANKS!!!!!!

  32. References • Association of Universities for Research in Astronomy, Inc. 1994. The Digitized Sky Survey http://stdatu.stsci.edu/cgi-bin/dss_form • Chereau F, Gates M, Kerr N, Marcos D, Marinov B. et al. 2010. Stellarium • Goldman, D. (2008). NGC 4088 in UMa. Last accessed 15th Nov. <http://dg-imaging.astrodon.com/gallery/display.cfm?imgID=135> • This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. 

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