WaterAstrochemistry

ISM Physics

Fundamental Astronomy

• ISM constituents

• ISM dust formation

• Ionization rate through astrochemistry

• THE way to study objects in astronomy

Dark H2• C+, HF

• accounts for ~30% of the molecular mass of the milky way

Pineda et al. 2013• context:

➡ Molecular hydrogen halo’s without CO around CO-traced molecular cloud

➡ formation/destruction of molecular clouds

• 0.4-0.7 solar masses of dust made in ~20 years!

SN 1987A

Mat

suur

a et

al.

2011

Short-lived Ions as probes• detection of OH+, H2O+ - completely new and provides a

unique measurement of the ionization rate of the diffuse ISM --- CH+ not new but now spectrally resolved

• key points: ➡ ions are short lived with a lifetime of 30 yrs x [1 cm-3/n(H2)]➡ needs high production rate -- if you know n(H2) you can

esimate the formation rate, i.e. ionization rate or trace energy

➡ direct link between extragalactic and galactic science -- this is from the diffuse ISM which fills a telescope beam

THE way to understand...

J. Bouwman+ DIGIT

IRAS 16293

Sgr B2 N

Orion KL

NGC6334 I

AFGL2591

OMC2 FIR4

Orion S

CHESS/HEXOS

15

10

5

0

TA (

K)

720700680660640

Frequency (GHz)

15

10

5

0

TA (

K)

720700680660640

Frequency (GHz)

15 L⊙

6 x 106 L⊙

8 x 104 L⊙

2 x 104 L⊙

2 x 104 L⊙

400 L⊙

8000 L⊙

15

10

5

0

T A (K

)

695690685680675670665660

Frequnecy (GHz)

CHESS/HEXOS

• near complete census (to sensitivity limit) of chemistry from simple hydrides to complex organics

• excellent relative calibration -- reliable fluxes to model tens to thousands of lines for a given species

• abundances, densities, temperatures, linewidths -- physics and chemistry of dense ISM

• legacy product

New Physical Insights

• molecular excitation - formation pumping

• SF energy output - CO ladder

H3O+ - Formation Pumping

30

29

28

27

26

log

N/g

El (K)0 500 1000

Trot = 162 K

Trot = 519 K

D. Lis

Water and Dynamics

• Dominates emission: key part of the water story in the interstellar medium

• tracer of dynamics more broadly -- infall from prestellar to low mass to high mass (Caselli - Mottram - Herpin)

Kristensen et al. 2012, 542, 8

Nisini et al. 2010A&A, 518, L120,Codella+ 2010

1. Water is made in prestellar phase under cold conditions as ice, D enrichments implanted.

2. Collapse seeds disk with water ice. initial suggestions are this is mostly unaltered.

3. Water vapor is readily detected on disk surface in inner and rarely in outer disk. Seen as ice in outer disk - midplane remains hidden.

Herschel has made a large part of the water trail clear.

Still need to characterize the young forming disk - the missing stage and see the midplane