An HI Survey of 2MASS Galaxies in the Zone of Avoidance Anja - - PowerPoint PPT Presentation

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An HI Survey of 2MASS Galaxies in the Zone of Avoidance Anja - - PowerPoint PPT Presentation

Aug 02, 2023 35 likes •288 views

An HI Survey of 2MASS Galaxies in the Zone of Avoidance Anja Schrder, SAAO/SALT, South Africa & R. Kraan-Korteweg, M. Ramatsoku, W. van Driel, T. Henning, J. Huchra Outline Introduction: the Zone of Avoidance A magnitude-limited

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SLIDE 1

An HI Survey of 2MASS Galaxies in the Zone of Avoidance

Anja Schröder, SAAO/SALT, South Africa

&

  • R. Kraan-Korteweg, M. Ramatsoku, W. van Driel, T. Henning, J. Huchra
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SLIDE 2

Outline

  • Introduction: the Zone of Avoidance
  • A magnitude-limited 2MASS galaxy sample
  • HI survey of the Northern ZoA
  • A massive cluster in the Pisces-Perseus filament
  • Outlook
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The Milky Way

25% of the optical sky is obscured by our Galaxy

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SLIDE 4

The origin of the motion of the Local Group

x

Great Attractor:

vLG = ~4000 km/s l=320o, b=0o

(Kolatt et al. 95) x

CMB:

vLG = ~600 km/s l=268o, b=27o

Lynden-Bell+ 1988

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SLIDE 5

Filling in the Gap

Aim: a magnitude- or volume-limited all-sky survey with a) redshifts b) redshift-independent distances Solution:

  • complement an existing survey in NIR and/or HI

=> 2MASS, blind HI surveys

  • fill in the ZoA with new observations
  • apply the TF relation to derive peculiar velocities [see Khaled’s talk]
  • combine with existing survey
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SLIDE 6

2MASS Redshift Survey (2MRS)

Huchra, Macri et al 2012:

  • Ks <=11.75 mag and detected at H-band
  • E(B-V) < 1.0 mag
  • |b| > 5.0 deg for 30 < l < 330 ; |b| > 8.0 deg otherwise

=> 45,086 sources

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SLIDE 7

2MRS-ZoA sample

2MASS extended source catalogue:

  • |b| < 10˚ => 145 294 sources
  • Ko ≤ 11.25 mag => 6642 sources
  • Galaxies => 3675 galaxies
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SLIDE 8

2MRS-ZoA sample

  • Galactic objects and blended stars
  • galaxies
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SLIDE 9

2MRS-ZoA sample

Contours: 2MASS star densities Galactic extinction stellar density

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2MRS-ZoA sample

  • 2MRS galaxies: 1778 + 610 (‘extra’)
  • 2MRS-ZoA galaxies: 1287
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Deep HIZOA survey (Parkes)

(Kraan-Korteweg)

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SLIDE 12

Nançay survey

Observations: 100m-class radio telescope

  • 500 km/s < vel < 10500 km/s

18 km/s velocity resolution 3.3 mJy/beam rms noise Results: 978 galaxies observed 212 galaxies detected 13 marginal detections => 23% total a few pointings have more than one detection

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SLIDE 13

Nançay survey: HI survey comparison

NRT targeted survey n = 225 HIZOA blind survey n = 883

Line width W50

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SLIDE 14

Nançay survey: HI survey comparison

NRT targeted survey n = 225 HIZOA blind survey n = 883 NIR-selected survey versus HI-selected survey

Line width W50

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Nançay survey: New detections

Vel: 0 – 2500 – 4500 – 6500 – 8500 - 10500

before NRT detections after

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Nançay survey: New detections

2500 < v < 4500 4500 < v < 6500

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WSRT survey: Pisces Perseus filament

PhD project Mpati Ramatsoku

[MNRAS 460, 923]

Westerbork Synthesis Radio Telescope

  • mosaic: 35 x 12 hr pointings
  • area: 9.6 sq.deg
  • velocity range: 2000 – 17000 km/s
  • velocity resolution: 16.5 km/s
  • spatial resolution: 23” x 16”

Two strong radio sources 3C 129 (4Jy) and 3C 129.1 (0.9Jy) => Pilot project for APERTIF HI surveys

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SLIDE 18

WSRT survey: Pisces Perseus filament

214 galaxies; => 65% with NIR counterpart Extinction A_K

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WSRT survey: Pisces Perseus filament

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SLIDE 20

155º < l < 165º ; -30º < b < 30º WSRT: 159º < l < 163º

WSRT survey: Pisces Perseus filament

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What’s next?

Northern ZoA:

  • Nançay TF survey (to complement 2MTF)
  • EBHIS: Effelsberg Bonn HI survey
  • shallow survey exists: 172 ZoA detections;
  • deep survey will be complementary to HIPASS

All-sky ZoA and flow field analysis:

  • Parkes observations of 2MRS-ZoA galaxies in the south
  • NIR observations of HI detections [see talk by Khaled Said]
  • TF analysis [see talk by Khaled Said]
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SLIDE 22

EBHIS-ZoA survey: New detections

Vel: -500 – 2500 – 4500 – 6500 – 8500 - 10500

before EBHIS detections after

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SLIDE 23

What’s next?

Northern ZoA:

  • Nançay TF survey (to complement 2MTF)
  • EBHIS: Effelsberg Bonn HI survey
  • shallow survey exists: 172 ZoA detections;
  • deep survey will be complementary to HIPASS

All-sky ZoA and flow field analysis:

  • Parkes observations of 2MRS-ZoA galaxies in the south
  • NIR observations of HI detections (see talk by Khaled Said)
  • TF analysis (see talk by Khaled Said)
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SLIDE 24

Future surveys

HI Surveys:

  • WALLABY: ASKAP HI all-sky survey

(PI Staveley-Smith & Koribalski)

  • WNSHS: Westerbork Northern Sky HI Survey

(PI Josza)

NIR Surveys:

  • UKIDSS Galactic Plane Survey (GPS)
  • VISTA Variables in the Via Lactea (VVV) and

VISTA Hemisphere Survey (VHS)

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SLIDE 25

Summary

  • ZoA: finding galaxies, determining redshifts and peculiar

velocities -> cosmic flow fields

  • NIR and HI surveys complement each other
  • New large-scale structures in the northern ZoA
  • A survey of a rich cluster in the Pisces Perseus filament
  • Future all-sky HI surveys together with the UKIDSS and

VISTA surveys will close that gap of the ZoA