Unveiling the Molecular Environment of the Carina Nebula The 2015 - - PowerPoint PPT Presentation

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unveiling the molecular environment of the carina nebula
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Unveiling the Molecular Environment of the Carina Nebula The 2015 - - PowerPoint PPT Presentation

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Unveiling the Molecular Environment of the Carina Nebula The 2015 Nanten2 Consortium Workshop February 6th David Rebolledo Postdoctoral Fellow University of Sydney University of New South Wales Motivation a b 0:30 The Carina Nebula

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Unveiling the Molecular Environment

  • f the Carina Nebula

The 2015 Nanten2 Consortium Workshop February 6th

David Rebolledo

Postdoctoral Fellow University of Sydney University of New South Wales

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Motivation

  • The Carina Nebula is one
  • f the nearest regions of

active star formation.

  • Located at 2.3 kpc, it is

the nearest extreme star formation region.

  • Excellent place for

studying clustered star formation, stellar feedback and triggered star formation.

288 287 286 Galactic Longitude Galactic Latitude 0:00 0:30

  • 0:30
  • 1:00
  • 1:30
  • 2:00
  • 2:30

288 287 286 Galactic Longitude

a b

[O III] Hα [S II] Parkes 3.4 cm continuum NGC3324

a- Smith et al. (2000) b- Huchtmeier & Day (1975)

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  • Previously considered as

as an evolved HII region with no current star formation activity.

  • However, infrared
  • bservations revealed

several candidates for sites of current star formation.

  • Those compact infrared

sources are located at the heads of dust pillars or dark globules behind ionization fronts

  • Recent high resolution

surveys at X-rays, optical and infrared wavelengths. However, radio has been absent.

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A fast visit to Mopra ...

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CO Survey of Carina with Mopra

Back in 2014 ...

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CO Survey of Carina with Mopra

Today!

8.5 deg2

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CO Survey of Carina with Mopra

12CO(1 → 0)

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CO Survey of Carina with Mopra

13CO(1 → 0)

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SED fitting

500µm

Herschel

Hi-Gal* (Molinari et al. 2010)

* The Herschel Infrared Galactic Plane Survey

500µm 70µm 160µm 250µm 350µm

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Fν = ΩBν(Tcold)(1 − e−τν)

τν = τ0(ν/ν0)β

β = 2 τ0 = 1

Tcold

ν0 Mgas

RDG

κν

Dust opacity Dust to gas ratio

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K

Tcold

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HI integrated intensity K km s−1

NHI atoms/cm2 = 1.82 × 1018

  • TBdv

MHI

McClure-Griffiths et al. (2005) The Southern Galactic Plane Survey (SGPS)

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12CO integrated intensity

MH2 Msun = 4.4

  • LCO

K km s−1pc2 XCO 2 × 1020cm−2/(K km s−1)

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log(MHI + MH2 Msun ) log( Mgas Msun ) MH2+HI Mgas

vs.

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log

  • XCO

cm−2/(K km s−1)

  • log( Mgas

Msun )

XCO = Mgas − MHI FCO

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Summary

With Mopra Telescope, we have mapped 12CO and 13CO

  • ver 8.5 deg2 across the Carina Nebula.

I fit Herschel SEDs of each pixel with a modified blackbody to obtain the temperature of the cold gas in the central part

  • f the Nebula.

Under the current assumptions, I found that atomic + molecular hydrogen mass overestimates the gas mass provided by the SEDs analysis. Xco factor is one order of magnitude smaller than the value commonly assumed. Range is about two orders of magnitude.