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External Galaxies
Eduardo BañadosRaffaella CapassoJonathan FreudlichAlina StreblyanskaPaloma Martínez
Ilhuiyolitzin VillicañaYasir EzzuldeenCelia Verdugo
Motivation
- Sample of external galaxies. CO detection
-EMIR E0/E2 CO(1-0) @ 115GHz & CO(2-1) @230 GHz
-Determine molecular gas mass from CO emission
Observing strategy
Sources:
M82; SSET 02, 17, 24, 25, 26, 27, 28, 29, 30
High Stellar Masses and Star Formation Rates
Collision of 2 galaxies OTF map
Observation preparation
sources:checking visibility in ASTRO
checking calibrators in XEPHEM
Observations preparationsetup:RECEIVER /CLEAR ! Clean receiverBACKEND /CLEAR ! Clean backends
RECEIVER E090 CO(1-0) 111.4 UI /Hor UI /Ver UI ! Select E0 as receiverRECEIVER E230 CO(2-1) 220.64 UI /Hor UI /Ver UI ! Select E2 as receiver
SWWOBBLER -20 +20 /TPHASE 0.5 ! Switching mode
BACKEND FTS /DEF
Observations results
targets observed: M82, SSET-17 (total: 0.5 hrs)
problems: bad weather, telescope out of order.
Results: Only detection in M82
Observations results
targets observed: M82, SSET-17 (total: 0.5 hrs)problems: bad weather, telescope out of order.Results: Only detection in M82
CO(2-1) cannot be observed at 1mm!(at rms~1K no detection)
CO(1-0) 12 min exp. time~0.2K rms
Fitting process
1 component 2 components
Class command: line 2
Analysis
Fitting results:
M82 (2 components) :
C1= 252.17+/-2.125 K km/s
C2= 155.78+/-1.817 K km/s
Ico = 407.95 K km/s (sum of both components)
30m @115GHz: Feff
=94, Beff=78
θ: 0.37’ CO(1-0) beamsize
λ: 0.26 cm
Then SCO = 2460 Jy km/s
Analysis
Mmol = αCO LCO (Bolatto et al 2013)
LCO
= 2453 SCO
Δv DL2/(1+z) D = 3.7 Mpc → LCO=9+/-0.2 K km s-1 pc2
X
CO=2x1020(K km/s)-1 → α
CO=4.3Msun(K km s-1 pc2)-1 For the MW
Then, MH2= 4.0 x 108Msun
Correcting for He (1.36): Mgas
= 5.4 x 108 Msun
Comparison with literature: Mgas
= 1.3 x 109 Msun
(Walter et al 2002)
Correcting for He (1.36): Mgas
= 5.4 x 108 Msun
Comparison with literature: Mgas
= 1.3 x 109 Msun
(Walter et al 2002)
We are observing just a fraction of the galaxy
Gas Mass
Kiit Peak 2.1mtBlue: BRed: HaGreen: V
LCN = 6.823 x 106 +/- 0.5 x 106 K km s-1 pc2 (CN @ 113.5 GHz)
LCN = 3.016 x 106 +/- 0.9 x 106 K km s-1 pc2 (CN @ 113.19 GHz)
L13CO
= 5.142 x 106 +/- 0.5 x 106 K km s-1 pc2
Other lines
Carilli & Walter 2013
Conclusions
● CO(1-0) (3mm) and other lines detected even in bad weather (pwv ~ 40 mm)
● CO(2-1) (1 mm) needs good weather
● Mgas
calculated in 5 x 108 Msun
(fraction of the total mass)