A Panoramic View of Star Formation in Milky Way: Recent Results from Galactic Plane FIR/Sub-mm Surveys

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2017

Publication Year

2020-08-26T11:08:05Z

Acceptance in OA@INAF

A Panoramic View of Star Formation in Milky Way: Recent Results from Galactic Plane FIR/Sub-mm Surveys

Title

ELIA, Davide Quintino

Authors

10.5281/zenodo.1153787

DOI

http://hdl.handle.net/20.500.12386/26835

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A PANORAMIC VIEW OF STAR

FORMATION IN MILKY WAY:

RECENT RESULTS FROM GALACTIC

PLANE FIR/SUB-MM SURVEYS

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Mo lin ari + 20 14 , PP VI

Large surveys forever

Importance of large panoramic surveys not only to obtain statistically significant samples of sources and structures, but also to investigate large-scale phenomena

(4)

Herschel-‐SPIRE 250 micron maps of the por:on of the Galac:c Plane observed in the FQS project.

12_{CO
(1-‐0)
map
integrated
over
the}

velocity range 8 -‐24 km s-‐1_.

The Forgotten Quadrant Survey

600 hr ESO project at ARO 12-m (IAPS-OAA-IRA)

A

12

_{CO and}

13

_{CO (1-0) survey of a strip (220° < l < 240°}

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Hi-GAL

The Herschel infrared Galactic Plane Survey

Galaxy-wide Census, Luminosity,

Mass and SED of dust structures at

all scales from massive YSOs to

Spiral Arms

Simultaneous 5-bands

(

70-160-250-350-500µm

) continuum

mapping of 720 sq. deg. of the Galactic

Plane (|

b

|≤1°)

With almost 900 hours observing time is the

largest OPEN TIME Herschel KP

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Four scientific work packages (WP1-4):

WP1 – diffuse structure (filaments, bubbles) analysis

WP2 – compact structure (clump) analysis

WP3 – distance estimation

WP4 – combination of WP1-3 into a global scenario of the Galaxy

as a star formation engine

one technical work packages

WP5

–

Tools and Infrastructures:

Database and Virtual Observatory Infrastructure

Data Mining Systems

3D Visual Analytics systems

Science Gateway

…other packages dedicated to dissemination, management and

coordination activities.

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VIALACTEA is statistics

Estimating completeness limits is not for the faint-hearted !

Molinari+ 2016, Merello+ 2017

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The Hi-GAL Compact Source

“Physical Catalog”

The underlying idea behind this catalog is to extract

physical information from the SEDs of the sources,

collected from 21 to 1100 µm.

Cross-correlation with other tracers represents

a further development of this work.

SED selection is performed in the 160-500 µm

range: only SED eligible for greybody fit are taken

into account.

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Source statistics

-71° < l < 68° 0° < l < 360° 70 µm 122971 141994 160 µm 292051 322827 250 µm 280258 355924 350 µm 161855 215134 500 µm 85880 110991

Hi-GAL is statistics

First-generation Hi-GAL Photometric Catalogues created using CuTEx

package (Molinari+11).

Molinari+2016, Merello+2017

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HI-GAL 5-BAND CATALOG (~9.4 X105 ENTRIES)

HI-GAL 5-BAND FILTERED CATALOG (~1.5 X105ENTRIES)

+

ANCILLARY PHOTOMETRY (MIR, SUB-MM), KINEMATIC DISTANCES

PHYSICAL PROPERTY CATALOG (~1.5 X105 ENTRIES)

INNER GALAXY (~105 _ENTRIES₎ OUTER GALAXY (~5 X104ENTRIES) Elia+ 2017, MNRAS Merello+ 2017, in prep. SED SELECTION GREY-BODY FIT

SEDS ARE FURTHER SPLIT IN A “LOW-”

(11)

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Clump demographics

PROTO-STELLAR, 24584 PRE-STELLAR, 34023 UNBOUND, 3831 PRE-STELLAR, 25648 UNBOUND, 12836 PROTO-STELLAR, 15834 PRE-STELLAR, 19195 UNBOUND, 1615 PRE-STELLAR, 14355 UNBOUND, 6066

“High-reliability” catalog “Low-reliability” catalog

whole catalog

with distance

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Source disposition in the inner Galaxy

Ranges corresponding to the tips of the Galactic bar (-30° < l < -20°,

19° < l < 33°) also studied in Veneziani+2017

u  Proto-stellar

u Pre-stellar

(let’s use this color convention throughout this presentation!)

Arm prescription

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Size distributions

•  The angular size is calculated starting from the one estimated by CuTEx at

250 μm.

•  Most sources fulfill the definition of “clump” (e.g., Bergin & Tafalla, 2007).

•  Given a distance, proto-stellar ones are, on average, more compact than

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Temperature distributions

<T

_pre

> = 12.0 K

<T

_proto

> = 16.0 K

0 10 20 30 40 T[K] 0 2000 4000 6000 Nsources 0 20 40 60 80 100 N(<T)/N tot (%)

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K a uf fm a nn & Pilla i (2 0 1 0 ) K rum holz & Mc K e e (2 0 0 8 ) -2 -1 0 1 Log(Σ/[g cm-2]) 0 500 1000 1500 2000 2500 3000 N -2 -1 0 1 Log(Σ/[g cm-2]) 0 500 1000 1500 2000 2500 3000 N 0 20 40 60 80 100 % On average, proto-stellar sources are denser than pre-stellar ones. 3rd_Larson’s rela:on

Mass-Radius relation

<Σ_pre> = 0.26 g cm-2 <Σ_proto> = 0.51 g cm-2

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Clump Mass Function Slope

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L

_bol

vs M

_env

diagram

1 10 100 1000 10000 M (MO •) 100 101 102 103 104 105 Lbol (L O • ) 90% 90%

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-2 -1 0 1 2 3 Log(L/M) 0 500 1000 1500 2000 2500 3000 Nsources -2 -1 0 1 2 3 Log(L/M) 0 500 1000 1500 2000 2500 3000 Nsources 0 20 40 60 80 100 N(<L/M)/N tot (%)

L

_bol

/M

_env

ratio

Cesaroni+(2015), Hi-GAL

sources detected in CORNISH

Reliable H

II

region candidates

can be searched among

sources above the

L/M > 22.4 L

_¤

/M

_¤

threshold.

1 10 100 1000 10000 M (MO •) 100 101 102 103 104 105 Lbol (L O • ) 90% 90%

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High-

L

/

M

sources

Compatible with typical

L

/

M

of H

II

regions

MIR-dark sources

Average temperature in the middle

between pre- and proto-stellar

0 10 20 30 40 T[K] 0 2000 4000 6000 Nsources 0 20 40 60 80 100 N(<T)/N tot (%)

u  candidate HII regions

u  MIR-dark

u  all proto-stellar

P a la dini+2 0 1 2

Two possible sub-classes

of proto-stellar sources

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High-

L

/

M

sources

Compatible with typical

L

/

M

of H

II

regions

MIR-dark sources

Average temperature in the middle

between pre- and proto-stellar…

…but these sources

do not constitute the

left tail of the L/M

distribution, and are

highly scattered in

the col-col diagram.

u  candidate HII regions

u  MIR-dark

u  all proto-stellar

-2 -1 0 1 2 3 Log(L/M) 0 500 1000 1500 2000 2500 3000 Nsources -2 -1 0 1 2 3 Log(L/M) 0 500 1000 1500 2000 2500 3000 Nsources 0 20 40 60 80 100 N(<L/M)/N tot (%)

Two possible sub-classes

of proto-stellar sources

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L bol /L subm m = 1 0 0 (Ma ury+, 2 0 1 1 )

L

_bol

/L

_submm

ratio

0.0 0.5 1.0 1.5 2.0 2.5 3.0 Log(L_bol/L_smm) 0 500 1000 1500 2000 2500 3000 N sources Equivalent of “Class 0”

L_submm calculated for λ > 350 µm

Bolometric Temperature

T_bol = 1.25 ×10−11 −∞νFν dν ∞

∫

F_ν dν −∞ ∞

∫

Segregation between pre- and proto-stellar sources appears more evident. The sub-sample of MIR-dark

proto-stellar sources constitutes the left tail of the proto-stellar distribution.

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Dust temperature vs evolutionary descriptors

•  Te m p e rat u re i t s e l f i s a va l i d

evolutionary indicator.

•  Pre-stellar sources follow relations

expected for the greybody (Elia & Pezzuto 2016), while for the same temperature proto-stellar sources generally appear more evolved.

20 25 30 35 T[K] 0.0 0.2 0.4 0.6 0.8 1.0 N HII /N proto [%] C lum ps hosting U C H II re gions (H ofne r+2 0 0 0 ) Lbol Lsubmm ∝ e−n hc 350kT n=1 ∞ ∑ _{Γ(5 +}n_{β + i)}i i=0 ∞ ∑ &_'(_350kThc ) * + 4+β+i & ' (( ) * ++ −1 L_bol M ∝ T 4+β _T bol∝ 4 +β 4 T

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“Moving away” SF regions

(Baldeschi et al. 2017, I)

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0.75 1 1.5 2 3 5 7 kpc M > 1282 r pc ! " # $ % & 1.42 Msun

M > 1282

r

pc

!

"

#

$

%

&

1.42

M

_sun