The Hunt for Ha in Markarian's Chain
Hunting for Ha (Part2) : Markarian’s Chain within the Virgo Cluster
Askar 151phq; AP Mach2 GTO
ASI6200MM, - Baader 6.5nm NB CMOS opt. filters
H: (197 x 550s 61Bin 1, Gain 200)
R,G,B: (142,113,114 x 120s, Bin 1, Gain 100)
L: (138x120s, Bin 1, Gain 100)
Total integration time = 46.7 hrs (Feb 4,12,13; Mar 13,15,16, Apr 12,13,16,17,18 2024)
This is Part 2 of my hunt for hydrogen (alpha signal) in Markarians Chain – specifically the now infamous “bridge” between MGC4435 in the eyes and M86 that has been noted in images by others. I was satisfied with my previous image in the area, except that only a hint of this bridge’s existence was seen in that image – compiled from 20 hours of exposure time. It was apparent that additional integration time, particularly using a Ha filter would be needed.
I was prepared to keep imaging this matter for as long as it was reasonably high in the sky, and the weather cooperated. Unfortunately, when the weather ended up clearing, the nearly full moon decided to park itself in Virgo, and I had to throw away about 12 hours of subframes (not included in the totals shown). I generally dislike selective colour / luminance / area masking – but I found I had to engage in these techniques to make the hydrogen signal reasonably evident, even with this considerable integration time.
The explanation for presence of a Ha signal “bridge” between and within the two galaxies is that these galaxies had collided in the past, and the M86 elliptical galaxy stole hydrogen from the once spiral NGC4438. Star formation has likely recommenced in both galaxies due to the disruption of the Ha from the spiral arms. Seeing an elliptical galaxy with any Ha signal within is a real rarity.
