The ATLASGAL catalogue of class I methanol masers Silvia Leurini - - PowerPoint PPT Presentation

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The ATLASGAL catalogue of class I methanol masers Silvia Leurini - - PowerPoint PPT Presentation

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The ATLASGAL catalogue of class I methanol masers Silvia Leurini INAF OA-Cagliari The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018 Outlook CH 3 OH masers Observational properties of

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SLIDE 1

The ATLASGAL catalogue of class I methanol masers

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

Silvia Leurini INAF OA-Cagliari

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SLIDE 2

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

Outlook

  • CH3OH masers
  • Observational properties of Class I CH3OH masers
  • Bright Class I CH3OH masers:…what are they good

for?

  • The ATLASGAL catalogue of Class I methanol masers

2

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SLIDE 3

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

Methanol masers

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Class I methanol (CH3OH) masers

  • Scattered around YSOs (up to a parsec)
  • Collisional excitation
  • astrophysical shocks

Class II methanol (CH3OH) masers

  • Located in the nearest vicinity of YSOs
  • IR radiation excitation from a massive

YSO

  • Regions of high mass star formation only

Sanna+2015 G023.01-00.41

✕ ✕

Navarete+in prep.

CO(6-5)+Spitzer

Voronkov+2006 Navarete+in prep.

CO(6-5)+Spitzer

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SLIDE 4

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

Class I masers: Pumping mechanisms

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Class I methanol (CH3OH) masers

  • First detection in the Jk=2−Jk=1E at 25 GHz in the late ‘80s, followed by the brighter

70−61-A+ and 4-1−30-E lines at 44 and 36 GHz (Barrett+1971, Morimoto+1985)

✕ ✕ ✕ ✕

(a) (b)

  • (J+1)-1−J0-E/(J+1)0−J1-A type series: their occurrence

can be explained from the basic properties of the molecule (i.e. collisional rates and selection rules)

  • J2−J1-E series: ad hoc additional preference for the Δk =

3 collisions over Δk = 2 (Johnston+1992), or totally unselective collisions (Cragg+1992)

collisional rates with large set of levels and H2 as collisional partner computed by Rabli & Flower 2010ab, 2011 ⇒ Working model for bright Class I masers (Leurini, Menten, Walmsley 2016)

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SLIDE 5

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

Class I masers…what are they good for?

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NOEMA 84 GHz

Class I masers have typical luminosities of ~ 10-6 L⊙ ⇒ completely unimportant energetically compared to Class II masers (L>10-6 L⊙ and up to 10-3 L⊙, Pestalozzi+2007)

  • signposts of interaction regions of shocks with dense ambient material
  • efficient outflow tracers, unaffected by extinction and strong at mm wavelengths

⇒ potentially a powerful tool for protostellar activity in extremely embedded objects

  • extremely sensitive to the physics of the emitting gas

⇒ multiline studies can constrain the temperature and density structure of outflows and…we have a working model for bright Class I masers! ✕ ✕ ✕

  • utflows

cloud-cloud collision SNRs expanding HII region

Sobolev+1992,Salii+2002 HM: Plambeck & Menten 1990+ LM: Kalenskii et al. 2010a,b Yusef-Zadeh+2008+ Pihlström +2014 Voronkov+2010,2014 Sobolev+1992+ Voronkov+2010 Gómez-Ruiz+in prep.

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SLIDE 6

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

6

The ATLASGAL catalogue of Class I methanol masers

200 massive clumps in four evolutionary phases of massive SF:

  • 70 µm-weak clumps with no embedded point-like source ⇒ candidates starless/prestellar

sources

  • 24 µm-quiet clumps with compact point sources at 70 µm ⇒ sources in early protostellar

phase

  • MIR-bright clumps with embedded YSOs strong at 8 µm and 24 µm ⇒ sources hosting

YSOs

  • MIR-bright clumps with cm continuum emission ⇒ sources associated with a UCHII

region

Spitzer 3.6µm (blue), 8µm(green), and WISE 22µm (red) Csengeri, Leurini+2016

24 µm bright+cm 24 µm bright 24 µm dark 70 µm weak

time evolution

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SLIDE 7

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

7

IRAM 30m:

  • 3mm line survey including

5-1→40-E @ 84.5 GHz 80→71-A @ 95.1 GHz

  • Full sample
  • Δv=0.7 kms-1

Effelsberg:

  • 4-1→30-E @ 36.2 GHz
  • 70→61-A @ 44.1 GHz
  • Full sample observed
  • Δv=0.1 kms-1

SRT:

  • J2−J1series @ 25 GHz
  • low Δv (1.2 kms-1) survey of ~ 60 sources
  • high Δv (0.02 kms-1) deep integration on

detections

credits MPIfR credits IRAM credits INAF

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SLIDE 8

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

8

The ATLASGAL catalogue of class I methanol masers

24 µm bright+cm 24 µm bright 24 µm dark 70 µm weak

95 GHz 84 GHz 44 GHz 36 GHz 25 GHz

S(Jy) S(Jy) S(Jy) S(Jy) X(counts)

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SLIDE 9

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

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The ATLASGAL catalogue of class I methanol masers

Detection rates

25 GHz 36 GHz* 44 GHz 84 GHz 95 GHz

Total

37% 70% 33% 57%

70 µm weak

— 44% 44% 17% 22%

24 µm dark

14%* 73% 73% 34% 60%

24 µm bright

30% 71% 71% 39% 64%

24 µm bright +cm

52% 75% 75% 31% 58%

*essentially as the 44GHz line but data under examination *poor statistics

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SLIDE 10

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

10

The ATLASGAL catalogue of class I methanol masers

Detection rates

25 GHz 36 GHz* 44 GHz 84 GHz 95 GHz

Total

37% 70% 33% 57%

70 µm weak

— 44% 44% 17% 22%

24 µm dark

14%* 73% 73% 34% 60%

24 µm bright

30% 71% 71% 39% 64%

24 µm bright +cm

52% 75% 75% 31% 58%

*essentially as the 44GHz line but data under examination *poor statistics

⇒at least 44% of the prestellar candidates already host molecular outflows

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SLIDE 11

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

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Class I masers in ATLASGAL selected sources

− − −2 −1 1 2

G014.4918−0.1389 WISE + 870 m Contours

−

G14.49-0.14

NOEMA observations

  • SiO(2-1)
  • 84.5 GHz maser

⇒3 outflows are detected, one associated with the maser

Leurini+in prep.

44 GHz maser 84 GHz maser 95 GHz maser 36 GHz maser

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SLIDE 12

The big impact of a big dish: Science with the Effelsberg 100-m Telescope, Bonn, 20-21 February 2018

Summary and future perspects

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  • We selected 200 ATLASGAL clumps in different evolutionary phases of massive SF
  • We observed them in at least 4 masers (+ the 2−J1-E lines in 60 sources)
  • Class I masers are detected in all phases also in the youngest 70µm-dark clumps

⇒ Most comprehensive catalogue of Class I masers:

  • 1. are different masers associated with different evolutionary phases? 25 GHz

series most only in bright IR sources

  • 2. investigate shock structure with evolution

⇒ Ideal sample for follow-up interferometric studies to:

  • 3. investigate star-formation activity in very early phases
  • 4. investigate shock structure with evolution

Acknowledgements: Effelsberg 100m telescope: T. Csengeri, K. König, A. Kraus, B. Winkel and all the telescope staff for helping/ performing the observations and solving calibration issues! Sardinia Radio Telescope: S. Casu, P. Castangia, A. Melis, A. Tarchi, A. Trois and all the INAF-OAC staff for helping my way into a new telescope!