Gas Detection in Galaxies and Techniques Comparisons

Advisors: David Frayer and Ron Maddalena

Teresa AshcraftRich Cosentino

Lucas HuntKaren Lee-Waddell

Virginie Montes

Galaxies SelectedIRAS 16504+0228Seyfert 2 galaxyIRAS 12596-1529

IRAS 11257+5850Interacting galaxy

Galaxy 1 Galaxy 2 Galaxy 3

Observation Procedure

• Two data sets and three techniques:– frequency switching– position switching– “brain-dead” Maddelena Magic!! (freq+position

switch)• Observation time: 45 min per galaxy

Methods Comparison:Galaxy 1

Three methods Position and Frequency-position switch

RMSps = 7.7x10-3

RMSfsps = 6.6x10-3

Methods Comparison

RMSps = 7.2x10-3

RMSfsps = 5.8x10-3

RMSps = 8.4x10-3

RMSfsps = 7.3x10-3

Galaxy 2 Galaxy 3

RMS improvement: expected = 1.6 and observed = 1.2

Baseline ComparisonPosition switch Frequency-position switch

Galaxy 1 Galaxy 1

Galaxy 3 Galaxy 3

Baseline Comparison

Position switch Frequency-position switch

Galaxy 2 Galaxy 2

NHI = 1.7x1020cm-2 NHI = 1.6x1020cm-2

OH Spectral lineGalaxy 1

OH Spectral lineARP 220

Expected OH1665 : OH1667 = 5:9 (LTE) Observed OH1665 : OH1667 = 1:4 (Maser IR pumping)