The HI Universe: The The HI Universe: The ALFA and the Omega(HI)ALFA and the Omega(HI)

Patricia HenningPatricia Henning

Cosmic Web: galaxies and the Cosmic Web: galaxies and the large-scale structurelarge-scale structure

Socorro NM, 16 May 2008Socorro NM, 16 May 2008

HI surveys – the pastHI surveys – the past

HI Parkes All Sky Survey - HIPASS HI Parkes All Sky Survey - HIPASS (2004; Meyer, Zwaan et al.)(2004; Meyer, Zwaan et al.)

– All southern hemisphere, plus northern All southern hemisphere, plus northern extension to Dec = +25 degextension to Dec = +25 deg

– 5300 galaxies over 70% of sky5300 galaxies over 70% of sky– sensitivity 13 mJy per 15 arcmin beam, sensitivity 13 mJy per 15 arcmin beam,

at 18 km/s velocity resolutionat 18 km/s velocity resolution– 64 MHz BW, -1280 – 12,700 km/s64 MHz BW, -1280 – 12,700 km/s

– 280 galaxies with log M280 galaxies with log MHIHI < 8.5 in south < 8.5 in south

Meyer et al.Meyer et al.20042004

A deeperA deepersouthernsouthernhemispherehemisphereGalactic planeGalactic planesurveysurvey

Hydra wall andMonoceros extension

Puppis

Part of NormaSC

New

NewNew

PKS1343cluster

Puppisvoid

Extragalactic Arecibo L-Extragalactic Arecibo L-band Feed Array (ALFA) band Feed Array (ALFA) SurveysSurveys

Arecibo Legacy Fast ALFAArecibo Legacy Fast ALFA (ALFALFA) (ALFALFA) Team leaders: Giovanelli, Haynes (Cornell)Team leaders: Giovanelli, Haynes (Cornell)

Arecibo Galaxy Environments SurveyArecibo Galaxy Environments Survey (AGES) (AGES) Team leader: Davies (Cardiff)Team leader: Davies (Cardiff)

ALFA Ultra-Deep SurveyALFA Ultra-Deep Survey (AUDS) (AUDS) Team Team leader: Freudling (ESO)leader: Freudling (ESO)

Zone of Avoidance SurveyZone of Avoidance Survey (ALFA (ALFA ZOA) ZOA) Team leader: Henning (UNM)Team leader: Henning (UNM)

ALFA surveysALFA surveys

Arecibo Legacy Fast ALFA Survey - Arecibo Legacy Fast ALFA Survey - ALFALFAALFALFA– Ongoing, planned 7000 degOngoing, planned 7000 deg22 of high-galactic of high-galactic

latitude Arecibo skylatitude Arecibo sky– ~2.2 mJy per 3.5 arcmin beam, at 10 km/s ~2.2 mJy per 3.5 arcmin beam, at 10 km/s

velocity resolutionvelocity resolution– 100 MHz BW, -1600 – 18,000 km/s 100 MHz BW, -1600 – 18,000 km/s (+ new (+ new

broad-band spectrometer?)broad-band spectrometer?)

– 30,000 expected detections in ~5 years, to 30,000 expected detections in ~5 years, to z=0.06, hundreds of objects to HI mass to z=0.06, hundreds of objects to HI mass to 101088

Wedge plot of 2700 HI sources detected with Wedge plot of 2700 HI sources detected with ALFALFA (with 7.5% of survey)ALFALFA (with 7.5% of survey)

Z=0.05Z=0.05

ALFA Surveys (cont)ALFA Surveys (cont)

Arecibo Galaxies Environment Arecibo Galaxies Environment Survey - AGESSurvey - AGES– Ongoing, planned 200 degOngoing, planned 200 deg22 total on total on

13 selected areas (Virgo, groups, 13 selected areas (Virgo, groups, individual gals, filaments, Local Void)individual gals, filaments, Local Void)

– ~0.8 mJy per 3.5 arcmin beam (300 ~0.8 mJy per 3.5 arcmin beam (300 vs. 40 sec per beam), at 10 km/s vs. 40 sec per beam), at 10 km/s velocity resolutionvelocity resolution

– Will find low-mass galaxies to larger Will find low-mass galaxies to larger distances, but not as large-angle distances, but not as large-angle surveysurvey

Sky dist. and HI mass vs. distance for 100 Sky dist. and HI mass vs. distance for 100 HI sources in AGES Abell 1367 region HI sources in AGES Abell 1367 region sample (Cortese et al.). Solid line sample (Cortese et al.). Solid line detection limit S/N=6.5, W=200 km/s, detection limit S/N=6.5, W=200 km/s, dotted line same for ALFALFA, dashed dotted line same for ALFALFA, dashed HIPASSHIPASS

ALFA Surveys (cont)ALFA Surveys (cont)

Arecibo Ultra-Deep Survey – AUDSArecibo Ultra-Deep Survey – AUDS– Strategy: very long integration time on Strategy: very long integration time on

small patches of skysmall patches of sky– ~1000 hours on 0.36 square degree field, ~1000 hours on 0.36 square degree field,

75 hours/beam, few x1075 hours/beam, few x1088 M M00 at z=0.16 at z=0.16

– Stats should be sufficient to discriminate Stats should be sufficient to discriminate strong evolution vs. no-evolution scenariostrong evolution vs. no-evolution scenario

– Done precursor obs, not full sensitivity Done precursor obs, not full sensitivity survey yetsurvey yet

More science goal for More science goal for AUDSAUDS

– The cosmic web (reach ~10The cosmic web (reach ~101616 cm cm-2 -2 per 5 km/s channel, gas filling beam)per 5 km/s channel, gas filling beam)

– Low column density gas in the local Low column density gas in the local UniverseUniverse

– Extragalactic OH megamaser Extragalactic OH megamaser emissionemission

– Extragalactic HI absorptionExtragalactic HI absorption

The ALFA ZOA surveyThe ALFA ZOA survey

– Map obscured galaxies, large-scale Map obscured galaxies, large-scale structures at low Galactic latitudestructures at low Galactic latitude

– Provide redshifts for partially-obscured Provide redshifts for partially-obscured galaxies, particularly 2MASS for all-sky galaxies, particularly 2MASS for all-sky flow fieldsflow fields

– Two phases: shallow (5 mJy), deep (1 Two phases: shallow (5 mJy), deep (1 mJy)mJy)

– Deep survey will have ~sensitivity of Deep survey will have ~sensitivity of AGES over ~2-4 times sky area, HIMF AGES over ~2-4 times sky area, HIMF study over “fairer” volumestudy over “fairer” volume

Delphinus void Local void

Cygnus voidMicroscopium

void

Pisces-perseussupercluster

A539

A569

Orion void? Gemini void

Canis Majorvoid

Puppis filament

– Define edges of the Gemini, Canis Major, Define edges of the Gemini, Canis Major, Microscopium, and Cygnus voidsMicroscopium, and Cygnus voids

– Determine reality of Orion voidDetermine reality of Orion void– Confirm/Refute connection between Confirm/Refute connection between

A539 and A569A539 and A569– Probe newly-discovered nearby Probe newly-discovered nearby

Monoceros filamentMonoceros filament– Study HI in variety of densities, survey Study HI in variety of densities, survey

region not selected by LSSregion not selected by LSS

ALFA ZOA survey statusALFA ZOA survey status

– Survey began May 2008 - Hundreds Survey began May 2008 - Hundreds of hours, starting in inner Galaxy, of hours, starting in inner Galaxy, ~1000 square degrees~1000 square degrees

– Have completed two small, shallow Have completed two small, shallow “precursor” regions (38 sq deg near “precursor” regions (38 sq deg near l=40, 100 sq deg near l=190)l=40, 100 sq deg near l=190)

Inner Inner Galaxy: 10 Galaxy: 10 galaxies galaxies detected, detected, only 1 has a only 1 has a cataloged cataloged counterpart counterpart in any other in any other waveband waveband (IR)(IR)

Outer Outer Galaxy: 62 Galaxy: 62 galaxies galaxies detected, 49 detected, 49 have have counterparts counterparts 25 previous 25 previous redshiftsredshifts

Beyond ALFABeyond ALFA

Current generation ALFA surveys will yield Current generation ALFA surveys will yield ~several x 10~several x 1044 galaxies to z~0.1, will galaxies to z~0.1, will characterize the local HI mass function characterize the local HI mass function very well. (Arecibo capable of going very well. (Arecibo capable of going deeper, but confusion issues for high z, deeper, but confusion issues for high z, especially for blind surveys – beam about especially for blind surveys – beam about size of a cluster at z=0.25)size of a cluster at z=0.25)

HI detection beyond z = 0.1 has been HI detection beyond z = 0.1 has been achieved eg. z=0.28 with AO achieved eg. z=0.28 with AO (Catinella et (Catinella et al.)al.) also z=0.2 WSRT also z=0.2 WSRT (Verheijen et al.)(Verheijen et al.) and and z=0.24 in aggregate sense with GMRT z=0.24 in aggregate sense with GMRT (Lah et al.)(Lah et al.)

Neutral gas density in Universe (from Lah et Neutral gas density in Universe (from Lah et al. 2007). z=0 triangle is from HIPASS, large al. 2007). z=0 triangle is from HIPASS, large triangle is GMRT measurement. High triangle is GMRT measurement. High redshift points come from damped Ly-redshift points come from damped Ly- measurements. Consistent with constant! measurements. Consistent with constant! (note uncertainty in redshift range z = 0.1 – (note uncertainty in redshift range z = 0.1 –

1.5, corresponding to 2/3 age of Universe)1.5, corresponding to 2/3 age of Universe)

Cosmic star formation history Cosmic star formation history (Panter et al. 2007)(Panter et al. 2007)

Want record of HI over redshift Want record of HI over redshift with large evolution in SFR – with large evolution in SFR – where, how, is gas going to stars?where, how, is gas going to stars?

The next stepThe next step

A Goal: Evolution of HIMF. Most A Goal: Evolution of HIMF. Most of the action should be between of the action should be between z=0-1, Mz=0-1, MHIHI=(0.4 – 4) x 10=(0.4 – 4) x 1099 M Msun sun (vd (vd

Hulst et al. 2004)Hulst et al. 2004)

Predicted evolution of HIMF inhierarchical picture (Baugh et al. 2004). Dots are measured z=0 (Zwaan 03). Lines are predictions: solid z=0, dotted z=1, dashed z=3, dot-dashed z=4

Square Kilometer Array Square Kilometer Array pathfinderspathfinders E.g. ASKAP, 700-1800 MHz, with E.g. ASKAP, 700-1800 MHz, with

strawman 30 12m dishes with strawman 30 12m dishes with PAF, upgrade/expansion to 45. PAF, upgrade/expansion to 45.

5-sigma detectionsfor all southern-hemisphere, “shallow” (1 yr) surveystrawman, expansion FOV 30 deg2 – depends on success of PAF technology - N=600,000

Z=0.05 Johnston et al. 2007

ASKAP (cont.)ASKAP (cont.)

Similar simulationfor a deep (1 yr)single pointing,N= 100,000

Z=0.2 Johnston et al. 2007

New pathfinders includeNew pathfinders include

ATA – currently ATA-42, 6m dishes, FoV 2.45 ATA – currently ATA-42, 6m dishes, FoV 2.45 deg at 21cm. Full array could do deep HI deg at 21cm. Full array could do deep HI

MeerKAT – design decisions ongoing, aim 80 MeerKAT – design decisions ongoing, aim 80 12m dishes, single pixel feeds12m dishes, single pixel feeds

APERTIF/WSRT – developing FPA on WSRT, APERTIF/WSRT – developing FPA on WSRT, 25x FOV, 2x BW of current WSRT25x FOV, 2x BW of current WSRT

FAST – 500m dish, significant funding, FAST – 500m dish, significant funding, design developingdesign developing

What’s next?What’s next?

Next science step must be Next science step must be significant, or not worth funding significant, or not worth funding

Big step forward could be HIMF to Big step forward could be HIMF to z=1z=1

Want SB sensitivity, but also want Want SB sensitivity, but also want resolution to assign proper HI mass resolution to assign proper HI mass (e.g. at z=1, 20”=160 kpc, 5 km (e.g. at z=1, 20”=160 kpc, 5 km baseline)baseline)

10% SKA10% SKA

At z=1, reach 3.6 x 10At z=1, reach 3.6 x 1099 M Msunsun in 360 in 360 hours, 2.1 x 10hours, 2.1 x 1099 M Msunsun in 1000 hours in 1000 hours (Draft Phase I science case) But (Draft Phase I science case) But descope???descope???

To reach 5 x 10To reach 5 x 1088 M Msunsun ~750 day ~750 day survey with 10% SKA. Long time, survey with 10% SKA. Long time, but worthwhilebut worthwhile

If few pointings, long time, then If few pointings, long time, then prefer large FoV (of course)prefer large FoV (of course)

Key Science Project for the full SKA Key Science Project for the full SKA – 10– 1099 HI galaxies to z=1.5, for HI galaxies to z=1.5, for galaxy evolution, Cosmology (BAO)galaxy evolution, Cosmology (BAO)

Timescales, QuestionsTimescales, Questions

ALFA surveys complete ~5 years, new ALFA surveys complete ~5 years, new pathfinders underwaypathfinders underway

Connection to multi-Connection to multi-large optical/IR large optical/IR surveys (e.g. LSST) going concerns in the surveys (e.g. LSST) going concerns in the 2010’s, time will be ripe for deep HI surveys2010’s, time will be ripe for deep HI surveys

When/how do we best join forces with When/how do we best join forces with international community given US funding international community given US funding realities? Timescales plausible? SKA must realities? Timescales plausible? SKA must be capable instrument…Descope troubling…be capable instrument…Descope troubling…

Coordinate with other SKA-mid science/tech Coordinate with other SKA-mid science/tech issues: mid-freq Radio Synoptic SKAissues: mid-freq Radio Synoptic SKA