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