Finding the smallest gas-rich galaxies Betsey Adams ASTRON / - - PowerPoint PPT Presentation

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Finding the smallest gas-rich galaxies Betsey Adams ASTRON / - - PowerPoint PPT Presentation

Apr 16, 2023 290 likes •532 views

Finding the smallest gas-rich galaxies Betsey Adams ASTRON / Kapteyn Astronomical Institute Small Galaxies, Cosmic Questions 1 Aug 2019 John Cannon, Riccardo Giovanelli, Martha Haynes, Bill Janesh, Lilly Bralts-Kelly, Steven Janowiecki, Tom

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SLIDE 1

Finding the smallest gas-rich galaxies

Betsey Adams ASTRON / Kapteyn Astronomical Institute Small Galaxies, Cosmic Questions 1 Aug 2019

John Cannon, Riccardo Giovanelli, Martha Haynes, Bill Janesh, Lilly Bralts-Kelly, Steven Janowiecki, Tom Oosterloo, Susie Paine, Kathy Rhode, John Salzer, Nick Smith

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SLIDE 2

The gas-rich (HI) Universe

Velocity

ALFALFA HI Survey Mancera-Piña+ submitted

Flux

  • Observables:
  • Recessional velocity (distance)
  • Internal kinematics (total mass)
  • HI line flux -> HI mass
  • Features:
  • Field galaxies: isolated, blue, star-

forming

  • Disentangle environmental influence
  • vs. intrinsic properties
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SLIDE 3

The gas-rich (HI) Universe

  • Observables:
  • Recessional velocity (distance)
  • Internal kinematics (total mass)
  • HI line flux -> HI mass
  • Features:
  • Field galaxies: isolated, blue, star-

forming

  • Disentangle environmental influence
  • vs. intrinsic properties

Spekkens+ 2014

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SLIDE 4

What dwarf galaxies do we see in HI?

Leisman+ 2017

  • SHIELD: Nearby, bonafide low-mass dwarf galaxies
  • Distances ~ 5 -12 Mpc
  • MHI ~ 3-50 x 106 Msun
  • Mstar ~ 3-50 x 106 Msun
  • HI-bearing ultra-diffuse galaxies: distant, low surface

brightness dwarfs

  • Distances ~50-100 Mpc
  • MHI ~ 108 - 109 Msun
  • Mstar ~ 107 - 108 Msun

McQuinn+ 2014

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SLIDE 5

What about the ultra-faint regime?

  • Leo T
  • Most distant UFD
  • Only one that is gas-rich
  • Mstar ~ 2 x 105 Msun
  • MHI ~ 4 x 105 Msun
  • Fill out parameter space pre-

LSST?

Tollerud+ 2008

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SLIDE 6

Tollerud+ 2008

What about the ultra-faint regime?

  • Leo T
  • Most distant UFD
  • Only one that is gas-rich
  • Mstar ~ 2 x 105 Msun
  • MHI ~ 4 x 105 Msun
  • Fill out parameter space pre-

LSST?

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SLIDE 7

Tollerud+ 2008

What about the ultra-faint regime?

  • Leo T
  • Most distant UFD
  • Only one that is gas-rich
  • Mstar ~ 2 x 105 Msun
  • MHI ~ 4 x 105 Msun
  • Fill out parameter space pre-

LSST?

Tollerud+ 2008 Ryan-Weber+ 2008

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SLIDE 8

Tollerud+ 2008

What about the ultra-faint regime?

  • Leo T
  • Most distant UFD
  • Only one that is gas-rich
  • Mstar ~ 2 x 105 Msun
  • MHI ~ 4 x 105 Msun
  • Fill out parameter space pre-

LSST?

Ryan-Weber+ 2008

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SLIDE 9

Leo P: Pushing to the field UFD limit

  • Extreme, nearby galaxy discovered as an HI

source in ALFALFA

  • D=1.62 Mpc
  • MHI = 8.1 x 105 Msun
  • Mstar = 5.6 x 105 Msun
  • vrot = 15 km/s
  • 12 + log[O/H] = 7.17 (~3% solar)
  • Single star-formation region
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SLIDE 10

Leo P: Pushing to the field UFD limit

  • Extreme, nearby galaxy discovered as an HI

source in ALFALFA

  • D=1.62 Mpc
  • MHI = 8.1 x 105 Msun
  • Mstar = 5.6 x 105 Msun
  • vrot = 15 km/s
  • 12 + log[O/H] = 7.17 (~3% solar)
  • Single star-formation region

Bernstein-Cooper+ 2014

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SLIDE 11

Isolated HI clouds as candidate LG galaxies

9h29m45.00s 30m00.00s 15.00s 30.00s 45.00s

RA (J2000)

′00.0′′ ′00.0′′ ′00.0′′ ′00.0′′ ′00.0′′ 14h17m15.00s 30.00s 45.00s 18m00.00s 15.00s

RA (J2000)

+17◦24′00.0′′ 28′00.0′′ 32′00.0′′ 36′00.0′′ 40′00.0′′

Dec (J2000)

  • E. A. K. Adams+ 2013

By design: No apparent optical counterpart in SDSS data Feature: Confusion with Galactic HI halo cloud population Higher resolution HI to discriminate

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SLIDE 12 14h17m15.00s 30.00s 45.00s 18m00.00s 15.00s RA (J2000) +17◦24′00.0′′ 28′00.0′′ 32′00.0′′ 36′00.0′′ 40′00.0′′ Dec (J2000) 40.5 42.0 43.5 45.0 46.5 48.0 49.5 51.0 52.5 54.0

cz (km s−1)

Isolated HI clouds as candidate LG galaxies

  • E. A. K. Adams+ 2016
9h29m45.00s 30m00.00s 15.00s 30.00s 45.00s RA (J2000) +24◦04′00.0′′ 08′00.0′′ 12′00.0′′ 16′00.0′′ 20′00.0′′ Dec (J2000) 148.0 148.8 149.6 150.4 151.2 152.0 152.8 153.6 154.4 155.2 156.0

NHI,peak ~ 5 x 1019 atoms cm-2 NHI,peak ≲1019 atoms cm-2

By design: No apparent optical counterpart in SDSS data Feature: Confusion with Galactic HI & halo cloud population Higher resolution HI to discriminate

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SLIDE 13 14h17m15.00s 30.00s 45.00s 18m00.00s 15.00s RA (J2000) +17◦24′00.0′′ 28′00.0′′ 32′00.0′′ 36′00.0′′ 40′00.0′′ Dec (J2000) 40.5 42.0 43.5 45.0 46.5 48.0 49.5 51.0 52.5 54.0

cz (km s−1)

Isolated HI clouds as candidate LG galaxies

  • E. A. K. Adams+ 2016
9h29m45.00s 30m00.00s 15.00s 30.00s 45.00s RA (J2000) +24◦04′00.0′′ 08′00.0′′ 12′00.0′′ 16′00.0′′ 20′00.0′′ Dec (J2000) 148.0 148.8 149.6 150.4 151.2 152.0 152.8 153.6 154.4 155.2 156.0

NHI,peak ~ 5 x 1019 atoms cm-2 NHI,peak ≲1019 atoms cm-2 Likely Galactic halo cloud Possible HI in a "disk" -- potential "galaxy"

By design: No apparent optical counterpart in SDSS data Feature: Confusion with Galactic HI & halo cloud population Higher resolution HI to discriminate

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SLIDE 14 14h17m15.00s 30.00s 45.00s 18m00.00s 15.00s RA (J2000) +17◦24′00.0′′ 28′00.0′′ 32′00.0′′ 36′00.0′′ 40′00.0′′ Dec (J2000) 40.5 42.0 43.5 45.0 46.5 48.0 49.5 51.0 52.5 54.0

cz (km s−1)

Isolated HI clouds as candidate LG galaxies

  • E. A. K. Adams+ 2016

By design: No apparent optical counterpart in SDSS data Feature: Confusion with Galactic HI & halo cloud population Higher resolution HI to discriminate

NHI,peak ~ 5 x 1019 atoms cm-2

Garrison-Kimmel+ 2014

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SLIDE 15 14h17m15.00s 30.00s 45.00s 18m00.00s 15.00s RA (J2000) +17◦24′00.0′′ 28′00.0′′ 32′00.0′′ 36′00.0′′ 40′00.0′′ Dec (J2000) 40.5 42.0 43.5 45.0 46.5 48.0 49.5 51.0 52.5 54.0

cz (km s−1)

Isolated HI clouds as candidate LG galaxies

  • E. A. K. Adams+ 2016
9h29m45.00s 30m00.00s 15.00s 30.00s 45.00s RA (J2000) +24◦04′00.0′′ 08′00.0′′ 12′00.0′′ 16′00.0′′ 20′00.0′′ Dec (J2000) 148.0 148.8 149.6 150.4 151.2 152.0 152.8 153.6 154.4 155.2 156.0

By design: No apparent optical counterpart in SDSS data Feature: Confusion with Galactic HI & halo cloud population Higher resolution HI to discriminate

NHI,peak ~ 5 x 1019 atoms cm-2 NHI,peak ≲1019 atoms cm-2

RELHICs - column density corresponds to halo mass

  • f ~few x 109 Msun

Benítez-Llambay+ 2017

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SLIDE 16

Kinematics of galaxy candidates

Lily Bralts-Kelly, in progress

vrot ~ 6 km/s vcirc ~ 10 km/s

14h17m15.00s 30.00s 45.00s 18m00.00s 15.00s RA (J2000) +17◦24′00.0′′ 28′00.0′′ 32′00.0′′ 36′00.0′′ 40′00.0′′ Dec (J2000) 40.5 42.0 43.5 45.0 46.5 48.0 49.5 51.0 52.5 54.0

cz (km s−1)

Preliminary

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SLIDE 17

Distances to candidate galaxies

Deep optical imaging with WIYN/pODI reveals potential stellar component

Janesh+ 2017

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SLIDE 18

AGC 249525

  • 98% significance
  • D = 1.64 Mpc
  • Mstar ~ 0.2 - 4 x105 Msun
  • MHI = 3 x 106 Msun
  • DHI ~ 4 kpc
  • Mdyn ~ 108 Msun

Properties of candidate galaxies

Deep optical imaging with WIYN/pODI reveals potential stellar component

Janesh+ 2017

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SLIDE 19

AGC 249525

  • 98% significance
  • D = 1.64 Mpc
  • Mstar ~ 0.2 - 4 x105 Msun
  • MHI = 3 x 106 Msun
  • DHI ~ 4 kpc
  • Mdyn ~ 108 Msun

Properties of candidate galaxies

Deep optical imaging with WIYN/pODI reveals potential stellar component

Janesh+ 2017

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SLIDE 20

5/29 detections in total (Janesh+ 2019)

  • D = .35 - 1.6 Mpc
  • MHI ~ 0.2 - 30 x105 Msun
  • Mstar ~ 0.04 - 40 x 104 Msun
  • Only old stellar populations

Properties of candidate galaxies

Deep optical imaging with WIYN/pODI reveals potential stellar component

Janesh+ 2017

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SLIDE 21

Looking to the future

Apertif: Phased-array feed on WSRT MeerKAT: sensitive single-pixel feeds ASKAP: Phased-array feed FAST, Arecibo w/ ALPACA (40 beams)

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SLIDE 22

The data is flowing

UGC 8914 Mstar = 106 Msun MHI= 3 x 108 Msun

Apertif Early Science Data

Apertif Imaging Team

MIGHTEE (MeerKAT) 
 Early Science Data

MIGHTEE-HI and IDIA Pipelines Team

dwarf galaxy companion no previous redshifu

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SLIDE 23

Take-away messages

  • HI offers an important perspective on dwarf galaxies
  • HI surveys offer possibility of finding gas-bearing field ultra-

faint dwarf galaxies

  • Have found several (~2-5) potential candidates in ALFALFA
  • AGC 249525 is an excellent candiate with promising HI

properties and a potential stellar counterpart

  • Exciting times ahead with SKA pathfinders coming online