Frayer (1) Redshifted Molecular Gas – Evolution of Galaxies David T. Frayer (NRAO) ALMA-Band ALMA Band-2 (68-90 GHz) is a crucial missing band for astronomy. Before the GBT 4mm system, there was very limited sensitivity coverage below 80 GHz.

Frayer (2) ALMA Band-2 (4mm Rx) “Key Science” Fundamental Physics – With VLBI, probe the physics near the base of black hole jets in nearby galaxies {and measure the size of the galaxy via parallax of SagA*}. The Context of Star Formation – Deuterium species and dense gas tracers key for studies of cold cloud cores from which stars form. Origin of Life – Complex organic molecules and pre-biotic molecules in the ISM and comets which are key for studying the conditions from which life eventually forms (unexplored frequencies --- lots of discovery potential in astro/bio-chemistry). Galaxies Across Cosmic Time – CO(1-0) at intermediate redshifts where the evolution of galaxies is proceeding rapidly and dense gas tracers, such as HCN and HCO+, in local star- forming galaxies. ALMA-Band From the GBT 4mm Science Case

Frayer (3) What are the Bright Extragalactic Lines? ALMA Band-2 (67-90 GHz) Line Redshift Range 12CO: 0.28<z< CO: 0.2<z<0.64 HCN: 0<z<0.32 HCO+: 0<z<0.33 ALMA-Band FCRAO RSR: NGC253+M82 Intermediate redshift galaxies and (1-0) transitions are important for understanding galaxy evolution

Frayer (4) Star-Formation History from the Infrared ALMA-Band Magnelli, et al (Spitzer FIDEL-70um result) Why are LIRGs important? The bulk of the infrared EBL is at z~1, and the rapid evolution from now to z~1 is associated luminous infrared star-forming galaxies (LIRGs). Herschel and Spitzer Surveys found large numbers of z~0.2-1 LIRGS.  CO at intermediate redshifts key. ULIRGs LIRGs

Frayer (5) HST imaging of local IRAS LIRGs (part of GOALS sample – Great Observatories All-sky LIRG Survey) ALMA-Band What are LIRGs? -- Diverse systems of mergers and disks

Frayer (6) GBT/Zpectrometer CO(1-0) ALMA-Band H-ATLAS SDP.81(ON)+SDP.130 (REF, negative): CO(1-0) redshifts measured. (Frayer et al. 2011) GBT/Zpectrometer CO(1-0) and CARMA/PdBI CO(3- 2) observations of Herschel SMGs show wide range of L’[CO](3-2/1-0) ratios of ~0.6+/-0.4  Need 1-0 line for molecular mass measurements. Why CO(1-0)?

Frayer (7) VLA CO(1-0) Imaging ALMA-Band Observations suggest low-CO excitation for both the BzK’s and SMG samples  extended cold CO(1-0)? Imaging: Extended emission or separated clumps, outflows, disks, structure/kinematics  ALMA BzKs (Aravena et al. 2010) SMGs (Ivison et al. 2010): Why do we need spatial resolution?

Frayer (8) Comparison of ALMA,VLA, and the GBT for redshifted CO(1-0) ALMA-Band Detection levels for same amount of observing time Plot made in Aug 2012, before GBT 4mm upgrade

Frayer (9) Evolution Disks vs “Merger” Starbursts ALMA-Band Daddi et al. 2010b BzK’s and Tacconi et al disk selected sample compared with the SMGs. With CO(1-0) at intermediate redshift, ALMA-Band-2 can study the molecular mass evolution of the “disk sequence” in the transition epoch between z~0--1.

Frayer (10) Dense Gas in Local Galaxies ALMA-Band Gao & Solomon 2004: Dense gas traced by HCN better correlated with Lir than CO. SFE correlated with dense gas fraction.  HCN & HCO+

Frayer (11) ALMA-Band Significant HCO+/HCN variations in starbursts and AGN sources, although tracing similar densities. Kripps et al. 2008

Frayer (12) ALMA mapping CO, HCN, HCO+ (HCN & HCO+)/CO  measures dense gas fraction, star-formation efficiency HCN/CO strong enhancements  AGN, extremely compact IR sources (x-ray heating, IR pumping) HCO+/HCN ratio enhanced in star-forming regions (UV-field, SN shocks) ALMA-Band2 2013

Frayer (13) ALMA-Band Frayer et al Local example: VV114 merger system shows molecular gas and dust that peaks between the two main optical components. The mid-IR emission peaks on the extremely red J-K source in VV114 East

Frayer (14) ALMA-Band Imanishi et al HCO+ peaks on the star-forming regions with the CO and dust between VV114E&W, while HCN peaks on the strong mid-IR/extremely red VV114E component

Frayer (15) Variations of Molecular Lines in Nearby Galaxies, e.g. IC342 Meier & Turner 2005 ALMA-Band IC342: CO=green, HI=red

Frayer (16) 16 element scalable W-band FPA for the GBT ALMA-Band Argus is scheduled to be deployed at the GBT by November 2014 and is a collaboration between Stanford U. (PI Sarah Church), Caltech, JPL, Univ. Maryland, Univ. Miami, and NRAO. Frequency operation range: GHz Tsys~75K

Frayer (17) ALMA-Band GBT (9”) 1pixel GBT/ARGUS 16pixel GBT 100pixel ALMA 1” ALMA 5” ACA (23”) ALMA-TP (70”) Rms=1mJy/ beam per point 2.5min 1.2min 5hr3hr Rms=2mK per point 2.5min 122hr11min6min3s Map 3’x3’ with 1mJy/beam 18hr69min11min59min 80hr27hr Map 3’x3’ with 2mK 18hr69min11min6000hr9hr96min27s GBT vs ALMA Sensitivity: Estimated Observing Times Interferometers provide high-resolution data and good point- source sensitivity (mJy/beam), but lack sensitivity to extended emission (mK).

Frayer (18) ALMA-Band CASA Simulations to compare GBT vs ALMA+ACA+ALM A_TP 30dor 8um IRAC image – Rescaled from 2” pixels to 1” pixels. 30dor in the LMC is the most luminous star-formation region in the local group of galaxies.

Frayer (19) ALMA-Band GBT simulated HCN image: Total flux: 1.25 Jy Contours are (0.05, 0.1, 0.2, 0.4, 0.6, 0.8) x peak.

Frayer (20) ALMA-Band ALMA 5”image (50x12m dishes, full ALMA) Flux: Jy (7% of total flux) Contours (-0.1, , 0.05, 0.1, 0.2, 0.4, 0.6, 0.8)xpeak

Frayer (21) ALMA-Band ALMA in Total- Power Mode (4x12m dishes OTF maps) Note the lack of spatial information…. Not very useful for combining with data taken with ALMA’s resolution.

Frayer (22) ALMA-Band ACA image: (9x7m dishes) Shorter spacing recovers more of the emission. Flux= 0.40 Jy (32% of total flux)

Frayer (23) ALMA-Band ACA+TP image: Flux=1.16Jy (93% of total flux) Note that TP adds significant flux outside of the known emission regions.

Frayer (24) ALMA-Band Comparisons of simulations of the 30Dor region (10” resolution). GBT Above: ALMA using ACA+TP for clean model does well for bright central regions, but has edge effects and misses extended emission. Above: ALMA “feathered” with ACA+TP adds in extended emission throughout the map and does not do as good as job with bright central region.

Frayer (25) Concluding Remarks ALMA Band-2 Extragalactic Science:  Galaxy evolution via CO(1-0) at intermediate/low redshifts  Dense gas (HCN & HCO+) and molecular variations in nearby and redshifted starbursts Technical synergies of 67—116 GHz (ALMA Band-2+3 and GBT W-FPA development) GBT W-FPA could provide useful short- space data for ALMA images of extended sources ALMA-Band2 2013