1. The Science Case for Band 1 James Di Francesco Herzberg Institute of Astrophysics Victoria, BC, Canada

2. Band 1 - what is it? one of the 10 original bands intended for ALMA specs: 31.3 - 45 GHz, T Rx ~ 17-28 K, USB, HEMT design specs: 31.3 - 45 GHz, T Rx ~ 17-28 K, USB, HEMT design removed in early 2000’s during to save construction costs removed in early 2000’s during to save construction costs Science Case for Band 1 12 4 5 8 10 9 mm 350  m

3. Can Band 1 be restored? ALMA post-construction “development” plan, involves community, new directions ALMA post-construction “development” plan, involves community, new directions workshop held in Victoria, BC on 8-10 October 2008 to revisit the Band 1 science case workshop held in Victoria, BC on 8-10 October 2008 to revisit the Band 1 science case Band 1 enriches ALMA science at other bands, extends ALMA science to new regimes Band 1 enriches ALMA science at other bands, extends ALMA science to new regimes Science Case for Band 1 1 1 ALMA receiver optics 3 2 10 7 4 6 9 8 5

4. CO from High-Z galaxies molecular gas now detected at Z ~ 6, eg., SDSS J1148+5251 at VLA, IRAM (Walter et al. 2003) molecular gas now detected at Z ~ 6, eg., SDSS J1148+5251 at VLA, IRAM (Walter et al. 2003) CO data reveal excitation & kinematics of early star and galaxy formation CO data reveal excitation & kinematics of early star and galaxy formation ALMA Band 1 receivers could detect CO (2-1) from galaxies at Z = 4-6 and CO (3-2) from galaxies at Z = 6-10 ALMA Band 1 receivers could detect CO (2-1) from galaxies at Z = 4-6 and CO (3-2) from galaxies at Z = 6-10 Science Case for Band 1 J1148 CO (3- 2) 1” Walter et al. 2004 VL A

5. CO from High-Z galaxies molecular gas now detected at Z ~ 6, eg., SDSS J1148+5251 at VLA, IRAM (Walter et al. 2003) molecular gas now detected at Z ~ 6, eg., SDSS J1148+5251 at VLA, IRAM (Walter et al. 2003) CO data reveal excitation & kinematics of early star and galaxy formation CO data reveal excitation & kinematics of early star and galaxy formation ALMA Band 1 receivers could detect CO (2-1) from galaxies at Z = 4-6 and CO (3-2) from galaxies at Z = 6-10 ALMA Band 1 receivers could detect CO (2-1) from galaxies at Z = 4-6 and CO (3-2) from galaxies at Z = 6-10 Science Case for Band 1

6. CO from High-Z galaxies Science Case for Band 1

7. Sunyaev-Zel’dovich Effect Science Case for Band 1 hot electrons in galaxy clusters scatter CMB emission to higher energies, make “holes” in CMB at some frequencies SZE dependent on pressure, independent of redshift, used to derive H o, baryon fraction, cluster morphology SZE dependent on pressure, independent of redshift, used to derive H o, baryon fraction, cluster morphology

8. Sunyaev-Zel’dovich Effect Science Case for Band 1 ALMA Band 1 will reveal substructure in clusters, eg., shocks from recent mergers, eliminate systematics from low-res obs. could also begin to probe SZE in individual galaxies (giant Es), explore AGN/SMBH feedback and galaxy density profiles (DM) could also begin to probe SZE in individual galaxies (giant Es), explore AGN/SMBH feedback and galaxy density profiles (DM) ~3  K rms in 22” ~15  K rms in 10” John Carlstrom John Carlstrom

9. Dust in Protoplanetary Disks Science Case for Band 1 protostars can be surrounded by accretion disks of gas and dust, the birthplaces of planets cool disk dust emits thermal radiation in proportion to its opacity,    cool disk dust emits thermal radiation in proportion to its opacity,    opacity is related to grain size distribution and composition opacity is related to grain size distribution and composition Adams et al. 1988, following Draine & Lee 1984  ~ 2 30  m ISM T. Greene

10. Dust in Protoplanetary Disks Science Case for Band 1 protostars can be surrounded by accretion disks of gas and dust, the birthplaces of planets cool disk dust emits thermal radiation in proportion to its opacity,    cool disk dust emits thermal radiation in proportion to its opacity,    opacity is related to grain size distribution and composition opacity is related to grain size distribution and composition Adams et al. 1988, following Draine & Lee 1984  ~ 2 30  m ISM

11. Dust in Protoplanetary Disks Science Case for Band 1 spectral energy distributions of young stars can reveal grain growth from ISM dust, towards planet formation? since Band 1 samples longer wavelengths, it samples larger grains and provides longer lever arm to SEDs (departures?) since Band 1 samples longer wavelengths, it samples larger grains and provides longer lever arm to SEDs (departures?) free-free emission may be a problem, need lower too free-free emission may be a problem, need lower too  =0.7  0.1 Calvet et al. 2002

12. Radio Supernovae Science Case for Band 1 SNe radio lightcurves reveal density profiles of ejecta and circumstellar medium (CSM) SNe images show structure and size of shell, deceleration, geometric distance from expanding shock front method SNe images show structure and size of shell, deceleration, geometric distance from expanding shock front method Can also search for stellar remnant of explosion, ie., the pulsar wind nebula (PWN) Can also search for stellar remnant of explosion, ie., the pulsar wind nebula (PWN) SN 1987A (epoch 2006.9) ATCA at 9 GHz (0.4” FWHM) Gaensler et al. (2007)

13. Radio Supernovae Science Case for Band 1 SNe radio lightcurves reveal density profiles of ejecta and circumstellar medium (CSM) SNe images show structure and size of shell, deceleration, geometric distance from expanding shock front method SNe images show structure and size of shell, deceleration, geometric distance from expanding shock front method Can also search for stellar remnant of explosion, ie., the pulsar wind nebula (PWN) Can also search for stellar remnant of explosion, ie., the pulsar wind nebula (PWN) SN 1986J Red: 5 GHz VLBI Blue/White: 15 GHz VLBI Bietenholz, Bartel & Rupen (2004)

14. Radio Supernovae Science Case for Band 1 Band 1: radio SNe lightcurves, study galactic “factories,” rates, search for stellar remnants SN1987A: 0.12” FWHM, expect 300 beams across shell in 2014, get 100:1 dynamic range in 12 h SN1987A: 0.12” FWHM, expect 300 beams across shell in 2014, get 100:1 dynamic range in 12 h VLBI at 43 GHz with ALMA and VLA/VLBA/GBT, good uv coverage for low-dec sources, Sgr A*, lots of AGN, SNe? VLBI at 43 GHz with ALMA and VLA/VLBA/GBT, good uv coverage for low-dec sources, Sgr A*, lots of AGN, SNe? McDonald et al. (2001) SN remnants in M82

15. Radio Supernovae Science Case for Band 1 Band 1: radio SNe lightcurves, study galactic “factories,” rates, search for stellar remnants SN1987A: 0.12” FWHM, expect 300 beams across shell in 2014, get 100:1 dynamic range in 12 h SN1987A: 0.12” FWHM, expect 300 beams across shell in 2014, get 100:1 dynamic range in 12 h VLBI at 43 GHz with ALMA and VLA/VLBA/GBT, good uv coverage for low-dec sources, Sgr A*, lots of AGN, SNe? VLBI at 43 GHz with ALMA and VLA/VLBA/GBT, good uv coverage for low-dec sources, Sgr A*, lots of AGN, SNe? VLBI network with ALMA

16. …and more! Science Case for Band 1 debris disks chemistry of heavy organic species, carbon-chains, anions chemistry of heavy organic species, carbon-chains, anions free-free emission from jets/outflows free-free emission from jets/outflows measuring B-field using Zeeman effect (CCS) measuring B-field using Zeeman effect (CCS) spinning dust grains spinning dust grains dust chemistry in AGB envelopes dust chemistry in AGB envelopes masers masers We are working on a detailed Band 1 Science Case document to distribute online to the community.

17. ALMA band 1 vs. EVLA Q- band Science Case for Band 1

18. ALMA band 1 vs. EVLA Q- band Science Case for Band 1 ALMA and EVLA have, to first order, the same sensitivity at 31-45 GHz: 1  rms ~ 1  Jy in 12 hours ALMA advantages : few weather restrictions, greater no. of baselines (imaging quality), wider FOV (SZE/debris disks), southern hemisphere ALMA advantages : few weather restrictions, greater no. of baselines (imaging quality), wider FOV (SZE/debris disks), southern hemisphere EVLA advantages : finer spectral resolution (correlator), longer baselines, already in VLBA, northern hemisphere EVLA advantages : finer spectral resolution (correlator), longer baselines, already in VLBA, northern hemisphere A careful comparison between EVLA and ALMA is needed to determine how often Band 1/Q-band can be observed! A careful comparison between EVLA and ALMA is needed to determine how often Band 1/Q-band can be observed!

19. Summary and Final Points Science Case for Band 1 Band 1 would add 31-45 GHz capability to ALMA, perhaps extend to 50 GHz? Strong science cases exist for Band 1, that enhance or extend ALMA capabilities Strong science cases exist for Band 1, that enhance or extend ALMA capabilities Band 1 is relatively inexpensive, $10-20M, depending on design Band 1 is relatively inexpensive, $10-20M, depending on design relationship with EVLA needs to be carefully addressed relationship with EVLA needs to be carefully addressed input from community needed, please contact me if you wish to contribute! input from community needed, please contact me if you wish to contribute!

20. Science Case for Band 1 james.difrancesco@nrc- cnrc.gc.ca