looking for trees in the forest lion, bm seminar 5 june 2008 ruth buning (lcvu, amsterdam) wim...
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Looking for trees in the Looking for trees in the forestforest
LION, BM Seminar 5 June LION, BM Seminar 5 June 20082008
Ruth Buning Ruth Buning (LCVU, Amsterdam)(LCVU, Amsterdam)
Wim Ubachs Wim Ubachs (LCVU, Amsterdam)(LCVU, Amsterdam)
Michael Murphy Michael Murphy (Swinburne University, Melbourne)(Swinburne University, Melbourne) Lex Kaper Lex Kaper (UvA, Amsterdam)(UvA, Amsterdam)
Search for a variation of the proton-electron mass ratio on a cosmological timescale
Constants of natureConstants of nature
Why these numerical values?Why these numerical values? Really constant?Really constant?
(85) 61 672 1836.152
(96) 710 999 137.0351
e
p
m
m
Physical Review 82 (1951) 554
The proton-electron mass The proton-electron mass ratioratio
e
p
m
m
1
vibE
1rotE
ConstelecE
(Rigid rotor)
(Harmonic oscillator)
rotEvibrE
electrE
moleculeE
Molecular spectra, i.e. H2, NH3
Compare spectra over Compare spectra over ΔΔtt
– Astronomical data:Astronomical data: ΔΔt~Gyrt~Gyr
accuracy accuracy ~10~10-7-7
– Lab: Lab: ΔΔt~yr t~yr
accuracy accuracy →10→10-15-15
Empirical search for a Empirical search for a change in change in
QSO12 Gyr ago
Labtoday
90-112 nm ~275-350 nm
H2
Empirical search for a Empirical search for a change in change in
// and spectrum H and spectrum H22
Previous result, based on 76 lines in 2 Previous result, based on 76 lines in 2 QSO absorbers:QSO absorbers:
iabsi
i
i Kzz
1110
Accurately calculated
Lab: 5 x 10-9
QSO: (2-10) x 10-7
4σ
ii
i z10
absii
i zz 110
Decrease of 0.002% over the past 12 billion years PRL 96, 151101 (2006)
The QSO absorption The QSO absorption samplesample >2300 HI absorption systems>2300 HI absorption systems ~600 DLA’s~600 DLA’s 14 H14 H22 absorption systems absorption systems 6 useful6 useful 4 high-quality spectra4 high-quality spectra
Q0405: 37 lines at zQ0405: 37 lines at zabsabs=2.59=2.59
Q0347: 39 lines at zQ0347: 39 lines at zabsabs=3.02=3.02
Q2348: ~20 lines at zQ2348: ~20 lines at zabsabs=2.43=2.43 observed aug. observed aug. 07, VLT07, VLT
J2123: ~50 lines at zJ2123: ~50 lines at zabsabs=2.06 from Prochaska, Keck=2.06 from Prochaska, Keck
VLTVLT
Blue CCD chip Red CCD chip 1 Red CCD chip 2
Lyman- of quasar emissionzemis=3.0236
C IVemissionDLA at
zabs=2.615H2 regionzabs=2.426
DLA atzabs=2.93
DLA atzabs=2.426
QSO 1: Q2348 (VLT)
Wavelength (A)
H2 region
Resolution 103,000 ; zabs=2.0593
QSO 2: J2123 (Prochaska, Keck telescope)N
orm
aliz
ed fl
ux
H2
Ly
QSO 2: J2123
ResultsResults
QSO HQSO H22 spectra for spectra for // determination determination– Q0405: 39 linesQ0405: 39 lines– Q0347: 37 linesQ0347: 37 lines– Q2348: ~20 lines Q2348: ~20 lines – J2123: >50 linesJ2123: >50 lines
?
?
ConclusionsConclusions
2 2 → 4 objects→ 4 objects New result agrees on New result agrees on No consensus on systematicsNo consensus on systematics HD detection HD detection
Outlook: Observation J2123 with VLT Outlook: Observation J2123 with VLT next semesternext semester– 4 +16 hrs4 +16 hrs– Best object (bright, many HBest object (bright, many H22 lines, HD) for lines, HD) for
analysis analysis– Highest quality spectrumHighest quality spectrum
UVES: Ultraviolet – Visual Echelle Spectrograph
300-500 nm
420-1100 nm
slitviewslitview
CCD chipCCD chip
CCD chip: ThAr CCD chip: ThAr calibrationcalibration
Blue CCD chip Red CCD chip 1 Red CCD chip 2
Lyman- of quasar emissionzemis=3.0236
C IVemissionDLA at
zabs=2.615H2 regionzabs=2.426
DLA atzabs=2.93
DLA atzabs=2.426
QSO 1: Q2348 (VLT)
Wavelength (A)
Spectrum Q2348Spectrum Q2348DLA atzabs=2.615DLA at
zabs=2.426H2 region
Lyat zabs=2.615
Lyman limitat zabs=2.93
QSO 1: Q2348 (VLT)
L0R0 line of H2
> 7 velocity components
QSO 1: Q2348N
orm
aliz
ed fl
ux
Parameters describing 1 Parameters describing 1 absorption lineabsorption line
Voigt profileVoigt profile 3 free (‘cloud’) 3 free (‘cloud’)
parameters:parameters:– b,z,Nb,z,N
molecular data:molecular data:– lab wavelengthslab wavelengths– oscillator strengthsoscillator strengths– damping damping
coefficientscoefficients
b (km/s)
(1+z)rest
N (molecules
/cm2)
LCVU/Orsay, Meudon
Parameters describing Parameters describing multiple absorption linesmultiple absorption lines
From the same From the same ground state ground state (J=0, J=1, etc.)(J=0, J=1, etc.)
From different From different ground statesground states
Extra fit Extra fit parameter: parameter:
z
bbN
z
bb
N1 N2
z,
z,
SeeingSeeing
H Lyman seriesH Lyman series
Energy levels in a diatomic Energy levels in a diatomic moleculemolecule
Electronic Electronic
VibrationalVibrational vv
RotationalRotational JJ
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