isms-conference champaign-urbana, 19 june 2014 wim ubachs vu university amsterdam vlt pda-xuv...
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ISMS-ConferenceChampaign-Urbana, 19 June 2014
Wim UbachsVU University Amsterdam
VLT PDA-XUV
High-resolution molecular spectroscopy of H2
at 10% the age of the Universe;Testing the constancy of physical law
Ti:Sa
Varying Constants ?
Bekenstein-Barrow –Sandvik – Mageijo – Light scalar fields f
1) Coupling to cosmologyVariation on cosmologicaltime scales
“matter dominated”
“dark energy dominated”
z ≈ 1
d
l
ceFFA
c
jLS mat
220
24
Coupling constants are free parameters in Standard Model
2) Coupling to matterdensity -> “chameleons”Coupling to gravity
Jacob Bekenstein
The dimensionless proton-electron mass ratio
m is a good test ground
Coupling constants interdependent in GUT
eQCD m/~
)75(15267245.8361e
p
m
M
K
Calculate Measure Determine
Experimental approach: look at molecules
Spectroscopy is the most accurate branch of science
The shifting power is expressed via sensitivity coefficients Kμ
At least two lines with different sensitivities are necessary for constraining Δμ/μ.
+ Redshift z - or – a time interval
iabsi
i
i Kzz
1110
Empirical search for a change in =Mp/me
Compare H2 spectra in different epochs:
QSO12 Gyr ago
Labtoday
90-112 nm
~275-350 nm
Edwin Hubble
Accurately calculated
Lab: 4 x 10-8
QSO: (2-10) x 10-7
ii
i z10 absii
i zz 110
ln
ln
d
idiK
Lyman bandsB1S+
u - X1S+g
Werner bandsC1Pu - X1S+
g
94 nm 110 nm
Ki are different for each line; Ki are small !!
Km sensitivity coefficients in H2
1
pMem
vibE
1
pMem
rotE
ConstelecE
(Rigid rotor)
(Harmonic oscillator)
H2 laboratory wavelengthsThe Amsterdam “XUV-laser”
XUV-laser excitation
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)Salumbides et al, Phys. Rev. Lett. (2009)
For HD
Ivanov et al., Phys. Rev. Lett. (2008)
H2 laboratory wavelengths
FT-IR+Vis
XUV2-photondeep-UV
EF 1Sg+
B 1Su+
X 1Sg+
/Dl l ~ (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
>160 lines measuredat ~ 5 x 10-8
Some lines at < 1 x 10-8
VLT – UVESParanal, Chili
Keck – HIRESHawaii, VS
J2123 -005 at zabs=2.05
Unique spectrum from Keck; Resolution 110000 ; seeing 0.3”
37 panels
3071 – 3421 Å
~100 Hydrogen lines
7 HD lines
Spectrum from VLT; R=54000; seeing 0.8”; better SNR
“ComprehensiveFitting method”
Status of cosmological m-variation
Keck and VLT analysesconsistent !!
Q1441+272at z=4.2
March 2013
General message: | / |Dm m < 10-5
And J1237+0647 at zabs = 2.68957
Both CO (A1P-X1S+) and H2 observed strongly
(work in progress; UVES-VLT 2014 and laboratory)
Dependence of /Dm m on gravitational field
Spectrum of GD-133 White DwarfCosmic Origins Spectrograph - HSTWD=(GM/Rc2)=104Earth
Dependence of /Dm m on gravitational field
/Dm m < 5 x 10-5
Also in analysis: GD 29-38 at = 2 x 104 earth
To be published soon
> 1000 H2 lines !
Some conclusion
For redshifts z ~ 2 – 3.5 (10-12 Gyrs): 510
Rate of change:11510
yrt
At f=104 fearth:5105
Thanks & Acknowledgement
Edcel Salumbides
Julija Bagdonaite
Michael Murphy
MingLi Niu
LexKaper
MarioDapra