Siena College Alfalfa Group
Bobby Carroll
Kristie Dangerfield
Kevin Risolo
Danielle Seeley
Patti Carroll
Rose Finn
MKW 10
• MKW 10: A Group of Galaxies with a Compact Core- B. A. Williams– A poor cluster of galaxies (a small number of galaxies)
• (Ironically) Nine galaxies (of mpg < 15.5), with eight spiral members
– Five of which form a subsystem at the center of the cluster with observed tidal interactions via their HI profiles
• Embedded in a larger structure (3 degree diameter)• Central velocity = 6040 km/s• Standard deviation of the members = 150 km/s• Appears to be gravitationally bound
Disturbed Galaxies(Needed more hugs?)
– NGC 3820 shows definite signs of tidal damage• It hydrogen content per luminosity is the lowest of late-
type spirals in the group• Perhaps by NGC 3819?
– NGC 3817 is the least asymmetric of the subsystem• But its Gaussian profile is unusual given its inclination
of 45°– Still appears as a perfect double peak
– Galaxies outside the core appear unaffected by tidal interactions
Data Reduction: Finding Sources
• IDL to access the ALFALFA data– Used Gridview to identify sources both
visually and via computer recognition of galaxy locations in the “cube”• Went into Galflux to find the half width, flux,
and central velocity– Measurements are somewhat arbitrary, but more
or less accurate
• Put into our own catalogue
Gridview…… view
Sample Source
Comparison
• Compared our catalogue to ALFALFA catalogue– Able to match most every radio source
• However we did find a number of galaxies we had that the ALFALFA catalogue didn’t have
– We found all the galaxies they had» But not all their radio sources
– Look into this further, see which ones are missing?» Are they of importance?
Comparison II
• Took the ALFALFA catalogue and compared it to the SDSS– See which radio source galaxies have
optical counterparts– And which optical galaxies have no radio
counterpart
MKW 10 Group
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N 3820
N 3819
Zw 68-044
Zw 68-046
N 3833
N 3825
N 3822
N 3817
U 6647
N 3820
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N 3819
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Rectangular Search
61 Objects Found
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Dec
redshift
RA between 173.545 and 177.545 AND Dec between 8.306 and 12.306
Morphology
• Based off the optical images observed• Found:
– 27 elliptical galaxies– 16 spiral galaxies– 4 barred spiral galaxies– 4 lenticular galaxies– 10 irregular galaxies
Master CatalogGoal: merge radio and optical data into one catalog
Step1:
-Radio catalog - 163 detections
after velocity cut - 77 detections within 4600-7600(km/s)
-match Radio to SDSS Spec catalog - 33 galaxies
-match Radio to SDSS Phot catalog - 8 galaxies (r<18)
Step 2:
- no match with SDSS add - 36 galaxies
Step 3:
-go through SDSS Spec catalog
if not match to HI add - 39 galaxies
Position
Redshift
Color-Magnitude Diagram
HI Mass
Stellar Mass