Photodissociation in AstrochemistryPhotodissociation in AstrochemistryLeiden, 5 Feb. 2015Leiden, 5 Feb. 2015

Wim UbachsWim UbachsVU University AmsterdamVU University Amsterdam

Molecular hydrogen in the photosphere ofWhite Dwarfs

H2 in space

Copernicus (1972-1981)

FUSE (1999-2007)

IUE (1978-1996)

1970

Keck

VLT

Earth-based observations of H2; in high redshift quasar sightlines

Spectrum of J2123—001 at z = 2.05

on ground March 2013

Q1441+272 ; the most distant H2 absorberzabs = 4.22 ; 1.5 Gyrs after the Big Bang

Bagdonaite et al.Phys. Rev. Lett. Feb 2015Arxiv:1501.05533

Astroph. J. Lett. 766, L18 (2013)

Cosmic Origins Spectrograph on HST (R ~ 20,000)

Contributions of many lines in the B-X Lyman system

T=13,000 K

H2 laboratory wavelengths

XUV-laser excitation (1 + 1’ REMPI detection)

P(3) C-X(1,0)

R(0) B-X(9,0) line

Ubachs, Phys. Rev. Lett. (2004)Reinhold et al, Phys. Rev. Lett. (2006)

For HDIvanov et al., Phys. Rev. Lett. (2008)

H2 laboratory wavelengths Lyman bands

FT-IR+Vis

XUV2-photondeep-UV

EF 1g+

B 1u+

X 1g+

~ (5 – 50) x 10-9

Salumbides et al. Phys. Rev. Lett. 101 (2008) 223001Bailly et al., Mol. Phys. 108 (2010) 827

Two-step excitation Two-photon laser Doppler-free

FTIR and FT-VIS

1s2s

1s2

Determination of accurate wavelengths for Lyman bands

Baillyet al.Mol. Phys.(2010)

Experimentallevelenergies

B-state: Limited to J<13X-state: accurate calculations by Pachucki & Komasa et al.

Higher J (J>12): ab initio framework Abgrall/Roueff

Data base for hot H2

> 1500 linesincluded tomodel thespectrum

max max

0

)(

0

exp)12)((

exp)12)(()( v

v

vJ

J

vJI

vJI

vJ

kTE

JJg

kTE

JJgTP )("""'"' TPfNI JvJJvvc o l u m ni

ia b si

i

i Kzz

1110

EmpiricalEmpirical search for a change in search for a change in =M=Mpp/m/mee

d

dE

d

dE

EEd

dK XB

XB

ii ln

)(ln

Varying Constants ?

Bekenstein-Barrow –Sandvik – Mageijo – Light scalar fields

1) Coupling to cosmologyVariation on cosmologicaltime scales

d

l

ceFFA

c

jLS m a t

220

24

Coupling constants are free parameters in Standard Model

2) Coupling to matterdensity -> “chameleons”Coupling to gravity(test EEP)

Jacob Bekenstein

GD133: = (-2.7 +/- 4.7) x 10-5 z=0.0001820 (10)

GD29-38: = (-5.9 +/-3.8) x 10-5z=0.0001360 (8)

Dependence of on gravitational field

Insert fit parameters:

T and and z

Pv”,J” and Ki included

[5] Chardonnet, PRL 100, 150801 (2008)

SF6/Cs measurement

Thanks & Acknowledgement

Edcel Salumbides

Julija Bagdonaite

Michael Murphy

EvelyneRoueff

HerveAbgrall

SimonPreval

MartinBarstow

John Barrow

J. Bagdonaite, et al.Phys. Rev. Lett. 113, 123002 (2014)

E.J. Salumbides et al.ArXiv 1412.6920