galaxy clusters - 2025 ACF Winter

Question

Ram pressure stripping from a substance within these systems gives certain objects a distinctive “jellyfish” appearance. For 10 points each:

[10h] Name these systems. Scattering by electrons in these systems causes anisotropies (“an-eye-SAW-truh-peez”) in the CMB in the Sunyaev–Zeldovich effect.

ANSWER: galaxy clusters [accept galaxy groups; accept superclusters; prompt on clusters; reject “galaxies”]

[10m] The tails of jellyfish galaxies are notable for their high luminosity caused by this process. Post-merger galaxies usually experience a “burst” of this process, which occurs after exceeding the Jeans mass. A description is acceptable.

ANSWER: star formation [or stellar formation; accept equivalents like stars being created; prompt on starburst; prompt on gravitational collapse by asking “what other process does that lead to?”]

[10e] The intracluster medium, which strips material away from jellyfish galaxies, primarily consists of superheated plasma that emits radiation in this region of the EM spectrum. This region is the second-highest frequency band after gamma rays.

ANSWER: X-rays

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Summary


California	Main	Y	5	16.00	100%	60%	0%
Canada	Main	Y	6	16.67	100%	67%	0%
Florida	Main	Y	11	10.00	82%	18%	0%
Great Lakes	Main	Y	6	15.00	83%	67%	0%
Lower Mid-Atlantic	Main	Y	7	14.29	86%	57%	0%
Midwest	Main	Y	8	8.75	63%	25%	0%
North	Main	Y	10	13.00	60%	70%	0%
Overflow	Main	Y	4	15.00	75%	50%	25%
Pacific Northwest	Main	Y	12	16.67	92%	75%	0%
Southeast	Main	Y	12	11.67	75%	42%	0%
UK	Main	Y	4	15.00	100%	50%	0%
2025 ACF Nationals	2025-08-09	Y	3	20.00	100%	100%	0%
2024 ARCADIA at UC Berkeley	04/19/2025	Y	4	10.00	75%	25%	0%

Data


Berkeley F	Berkeley B	0	0	10	10
Stanford A	Berkeley A	0	10	10	20
Stanford B	Stanford C	0	10	10	20
UCSC	Berkeley D	0	0	10	10
Berkeley C	Berkeley E	0	10	10	20
Claremont Scripps	UCSB	0	10	10	20
UCLA B	UCI	0	10	10	20
Claremont Pitzer	UCLA D	0	0	10	10
UCLA A	UCSD Vices and Virtues	0	10	10	20
UCSD What Hath God Wrought	UCSD Two Running Violet V Forms	0	0	10	10
USC	UCLA C	0	10	10	20
Queen's B	McGill A	0	0	0	0
McMaster C	Toronto G	0	0	10	10
Toronto A	Toronto C	0	10	10	20
Toronto B	Guelph A	0	0	10	10
Toronto D	Toronto E	0	0	10	10
Toronto I	Carleton	0	0	10	10
McGill C	Toronto J	0	0	10	10
Toronto K	Toronto F	0	0	10	10
Toronto Metropolitan	Queen's A	0	0	0	0
Toronto H	Waterloo	0	0	10	10
McMaster A	Western Ontario	0	10	10	20
UCF A	ERAU B	0	10	10	20
UF A	FIU	0	10	10	20
UF B	Melbourne B	0	10	10	20
UCF B	ERAU A	0	0	0	0
UF D	UF E	0	10	10	20
UF C	USF	0	0	10	10
OSU C	MSU A	0	10	10	20
OSU B	CWRU B	0	10	10	20
CWRU C	CWRU A	0	10	10	20
Pitt A	CWRU D	0	10	10	20
Pitt B	Kenyon A	0	0	10	10
Pitt C	OSU A	0	0	10	10
Kenyon B	MSU B	0	0	0	0
James Madison	Roanoke	0	0	0	0
Virginia Tech A	Liberty A	0	10	10	20
North Carolina B	Liberty C	0	0	10	10
South Carolina A	NC State	0	0	10	10
Tennessee A	South Carolina B	0	0	0	0
North Carolina C	Tennessee B	0	0	0	0
Virginia A	Liberty B	0	10	10	20
North Carolina A	Virginia Tech B	0	0	10	10
George Mason B	Maryland D	0	0	0	0
Catholic University	Penn B	0	10	10	20
VCU A	George Washington A	0	0	0	0
Johns Hopkins A	George Washington B	0	10	10	20
Georgetown B	George Mason A	0	10	10	20
Georgetown A	Johns Hopkins B	0	0	0	0
Maryland A	Maryland B	0	10	10	20
NYU A	Johns Hopkins C	0	10	0	10
Maryland C	Penn A	0	10	10	20
Notre Dame E	George Mason C	0	10	10	20
Missouri A	Missouri B	0	0	10	10
Truman State	SIUE	0	10	10	20
WashU A	WashU D	10	10	10	30
WashU C	WashU B	0	0	0	0
Michigan B	Chicago B	0	10	10	20
Chicago C	UIC	0	10	10	20
Chicago D	Michigan D	0	10	10	20
Illinois A	Indiana A	0	0	10	10
Louisville A	Illinois B	0	10	10	20
Chicago A	Michigan A	0	10	10	20
Michigan C	Notre Dame C	0	0	10	10
Kentucky	Notre Dame A	0	10	10	20
Notre Dame B	Louisville B	0	0	10	10
Purdue B	Notre Dame D	0	10	10	20
Illinois C	Purdue A	0	10	10	20
Indiana B	Purdue C	0	10	0	10
Amherst A	Bowdoin A	0	10	0	10
Yale A	BC A	0	10	10	20
Brandeis Clemenceau	Amherst B	0	0	10	10
MIT A	Brandeis Orlando	0	10	10	20
Brandeis Wilson	Harvard	0	10	0	10
Brown B	Bowdoin B	0	0	0	0
Brown C	Brandeis Lloyd George	0	0	10	10
BU	Cornell-UG	0	0	10	10
MIT B	Tufts B	0	10	10	20
Brown A	Tufts A	0	0	10	10
Williams	BC B	0	0	10	10
Dartmouth	Yale B	0	0	10	10
British Columbia B	Simon Fraser	0	0	10	10
Alberta	British Columbia A	0	10	10	20
Washington B	British Columbia D	0	10	10	20
Edinburgh B	LSE B	0	10	10	20
Manchester B	Bristol A	0	10	10	20
Cambridge A	Warwick B	0	10	10	20
ESF	Binghamton A	0	10	0	10
RIT A	Binghamton B	0	0	10	10
Rochester	Cornell-DII	0	0	10	10
RIT B	Syracuse	0	0	10	10
British Columbia C	Washington A	0	0	10	10