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Messier 88 (NGC 4501)
Travis Hanko

Messier 88

Fifty-Eight Million light years away, in the Virgo Galaxy cluster, lies this bright object: Messier Object 88 (M88), which can also be classified as NGC 4501. It lies in the constellation Coma Berenices, and was discovered by Charles Messier in 1781. His entry for M88’s description is as follow,

“Nebula without star, in Virgo, between two small stars and one star of the sixth magnitude, which appear at the same time as the nebula in the field of the telescope. Its luminosity is one of the faintest, and resembles the one reported in Virgo, No. 58.”

Today, with all our scientific advances and technology, we have determined that M88 is, in fact, not merely a “nebula without star,” but a non-barred spiral galaxy, classified as an Sbc spiral, at a highly inclined angle of 62.9°. This inclination can be seen from the fact that the galaxy is in the shape of a circular disk, but appears to us as a football shape. This galaxy is also classified as a type 2 Seyfert Galaxy. These kinds of galaxies have narrow spectral line emission from the galaxy core, emitted perpendicularly from the galactic disk plane. These cannot be seen with visible light, and do not appear on normal images. What we can see with normal images, however, is that this galaxy is pretty blue. Yes, there is a yellow spot in the center around the active galactic nuclei, but for the most part, this galaxy is blue in color. This color indicates, based on scientific research, that this galaxy is a relatively young galaxy and has lots of new star formation happening within the spiral arms. The yellow center indicates a lack of star formation at that point. SN 1999cl (Supernova number 1999cl)

 

In 1999, a supernova of type Ia was discovered within this galaxy. This supernova was found by the Lick Observatory Supernova Search Team (LOSS) on May 29, 1999, although it was photographed the day before by Jeff MacQuarrie. It reached a maximum magnitude of 13.6 on June 12 of the same year. The arrow points to the supernova in the black and white image shown below.

 

This galaxy was calculated to be 93,000 light years wide using the small angle approximation. Using a distance of 18.055 Mpc (distance from original data off of NED’s website), and an angular size of 0.090 radians (using distances in pixels on my image and a conversion factor to of 1.32” per pixel), the width was calculated using the following formula (Equation 1) where “theta” is the angle in arcseconds, “l” is the width of the object, and “d” is the distance to the object.

Theta = l / d (Equation 1)

The inclination angle of this object was also calculated from the image taken. Using the number of pixels for the small and large radii, a simple trigonometric function was used below (Equation 2). With a large radius (“ b ”) of 245.84 pixels, and a small radius (“ a ”) of 112.06 pixels, the angle of inclination (“ i ”) was calculated to be 62.9 degrees.

cos(i)=b/a (Equation 2)

 

The images used for the picture seen at the top of the page were taken at Calvin's Rehoboth observatory. There were 10 exposures of clear at 60 seconds each, 16 exposures of blue at 360 seconds each, and 3 exposures of both green and red at 360 seconds apiece (totalling to 130 minutes of exposure time). These images were then cleared up using a master flat image, as well as a master dark image and a master bias image. They were then combined into one photo and the color was edited to fit reality.

References:

Frommert, Hartmut, and Christine Kronberg. "Supernova 1999cl in M88." SEDS, 11 Aug. 2005, messier.seds.org/more/m088_sn99cl.html. Accessed 28 Apr. 2017.

Onodera, S., Y. Sofue, J. Koda, H. Nakanishi, and K. Kohno. "Observations of the Non-barred Seyfert 2 Galaxy NGC 4501." , University of Tokyo, Japan, 2002. Accessed 28 Apr. 2017.

Espenak, Fred. "M88." AstroPixels.com, 29 June 2011, astropixels.com/galaxies/M88-01.html. Accessed 28 Apr. 2017.

"NED results for object Messier 088." NASA/IPAC Extragalactic Database. Accessed 28 Apr. 2017.

Bishop, David. "Supernova 1999cl in M88." Latest Supernovae, 3 Dec. 2001, www.rochesterastronomy.org/snimages/sn1999/sn1999cl.html. Accessed 28 Apr. 2017.

Right Ascension (J2000) 12:31:59.16
Declination (J2000) +14:25:13.4
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B, (300s x 16) V, and R (300s x 3); C (60s x 10)
Image dimension 1092x736 pixels; 23.8x16.1 arcminutes
Date/time observed March 16, 2017, 06:54 UTC

 

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