Galaxies of Many Colours: Star Formation Across Cosmic Time z=0, t=13.798+/-0.037x10 9 years (Now)
And if you want to study the initial conditions for star formation the colour is black Dense Gas SDC335: N 2 H + J=1-0 Mopra 30 ALMA 5
ALMA Dust Continuum Emission NASA Hubble Orion Trapizium cluster SDC335 in fewx105 yr? Size (pc) Mass (103 Msun) SDC335 2.4 5.5 B0.5-B1 + 2x B1.5-2.0 Centre 1.2 2.6 Three stars M>9.7Mo MM2 0.057 65 Msun MM1 0.054 550 Msun Region (Peretto et al 2013; Avison et al 2015) Can form ~750 stars down to M=0.08Mo using only ~5% of total mass
The Hot Dense Gas in W49: A Possible Analogue of Extragalactic Starbursts Gary Fuller Jodrell Bank Centre for Astrophysics & UK ALMA Regional Centre Node, University of Manchester Floris van der Tak (SRON), Rene Plume (Calgary) Zsofia Nagy (SRON/Toledo), Helen Roberts (Manchester)
Introducing W49N (Wu et al 2014) Mass 106 M, L~107 L -> L/M~10 D=11.4 kpc 30 O stars in central cluster. One star O2-3.5If*, 90-250 M (Galvan-Madrid et al. 2013) CO 1-0 (Gwinn et al 1992, Alves & Homeier 2003,Wu et al 2015)) C18O 1-0
JCMT Spectral Legacy Survey Spectral imaging survey using HARP/ACSIS on JCMT 330 GHz to 373 GHz, 1 km/s channels Fully sampled 2 x2 field, 15 beam (0.8 pc at W49) Four targets: Photon dominated region: Orion Bar Low mass protobinary: NGC1333 IRAS4 High mass protostar: AFGL2591 Galactic starburst: W49A (Plume et al 2007)
W49 Data (Nagy et al 2015) HCN J=4-3
Survey Depth & Uniformity
W49: Line Richness 255 lines from 63 species 41 SO 2 lines plus 33 34 SO 2 26 CH 3 OH
W49 Spectra
HCN,HNC, HCO + J=4-3 N E SW Integrated Intensity HCO + J=4-3 Infall profiles - Infall? (Roberts et al. 2011)
Centre East North Southwest
HCN Models (Roberts et al. 2011)
Submm-HCN Diagram: toward the submm-version of the BPT-diagram HCN(4-3)/CS(7-6) integrated intensity ratio 16 14 12 10 8 6 4 2 0 AGN Buried-AGN LX~2E43 erg/s SB Filled: Interferometer Empty: Single Dish SB-dominated N7469 N1068 (AGN) N4418 N1097 LX~7E40 erg/s AGN-dominated N1068 (APEX) IRAS12127-1412 N1068 (W-knot) LX~1E43 erg/s N1068 (E-knot) Izumi et al. 2015b submitted to ApJ (updated from Izumi et al. 2013) 0 0.5 1 1.5 2 2.5 3 3.5 4 HCN(4-3)/HCO + (4-3) integrated intensity ratio
PDR or XDR? (Meijerink et al 2007)
W49: Warm and Hot H 2 CO Line Ratio H 2 CO: 110 K HCN/HNC: 75 K H 2 CO: >300K HCN/HNC: 100K 0.8pc + (HCN/HNC/HCO Roberts et al 2011 H CO Nagy et al 2012) 2 H 2 CO: 90 K HCN/HNC: 40 K H 2 CO: 90 K HCN/HNC: 40 K
Origin of the Hot Gas Mechanical heating from stellar winds, bipolar outflows, UCHII region expansion: 30 O stars in central cluster ~850 L Radiative heating: 10-3 -10-2 of 6x10 6 L X-ray heating: 0.1 L (Tsujimoto et al 2006; Meijerink & Spaans 2005) Gas-grain heating: <30 L Mechanical & UV heating dominate
Radiation Field Tracers 14µm 21µm HCN HNC (Aalto et al 2015)
W49: Lines from Vibrational States Rotational lines in vibrationally excited states Four J=4-3 lines of HNC & HCN Plus HC 3 N 9 v6 lines 8 v7 lines 9 lines of SO 2 v2=1 IR pumped Extended First detection of HNC vibrational lines in a SFR H 13 CN HNC HCN HC 3 N v6=1 HC 3 N v7=1
W49: Excitation Conditions
Kinematic Signatures? Shock tracers No clear kinematic signatures - Environments well mixed in beam
Comparison with other regions Galactic PDRs Galactic shocks PDR Models
W49: Extragalactic Comparison Physical Properties NGC1068 & M82 from results from Aladro et al 2011, 2013
W49: Extragalactic Comparison Chemical Properties NGC1068 & M82 from results from Aladro et al 2011, 2013
Recombination Line ALMA Cycle 0 Observations of NGC253 Belatto et al (2013), Leroy et al (2015), Meier et al 2015
NGC253: H40α (Bendo et al 2015) 1.9 x1.6 beam 28 pc Declination (J2000) -25:17:10-25:17:20 10-1 10-0 Jy km s -1 arcsec -2 I(H40 ) 00:47:34 00:47:33 Right Ascension (J2000)
Extinction & SFR Line to continuum ratio Need to correct for dust ~30% from dust T e =3700-4500 K Consistent with previous estimates and Milky Way GC If dust 50% of emission, T e =2500-3000 K SFR 1.73+/-0.12 M yr -1 Q=3.2+/- 0.2 x 10 53 s -1 Density 10 3 cm -3 Previous values: <4.9 M yr -1 (SNR remnants 2.3 GHz Rampadarath et al 2014) 4.9 M yr -1 (25 GHz contiuum synchrotron calibration? Ott et al 2005) Q factor 3 above or below (Puxley et al 1997, Kepley et al 2011, Rodriguez-Rico et al 2006) Extinction Compare extinction predicted Brγ and Paβ with Engelbracht et al (1998) ALMA Measured A K 4.2+/-0.2 0.87+/-0.16 A J 5.0+/-0.2 2.00+/0.36
Velocity Structure Declination (J2000) -25:17:10-25:17:20 200 300 km s -1 v(h40 ) 00:47:34 00:47:33 Right Ascension (J2000) Rotation? Base of outflow?
Conclusions Spectral imaging survey of W49 covering 330-373 GHz detecting 255 transitions of 63 species Excitation analysis of 14 species including complex species CH 3 CCH, CH 3 CN & CH 3 OH Chemistry driven by shocks & UV probably, but hard to disentangle W49 is a reasonable, but less extreme, analogue of an extragalactic starburst ALMA observations of H40α provide an estimate of SFR and extinction in NGC253 Roberts et al 2011; Nagy et al 2012, 2015; Bendo et al 2015