CONSTRAINING CHANGES IN THE PROTON-ELECTRON MASS RATIO WITH INVERSION AND ROTATIONAL LINES

Journal Article · Thu Feb 10 04:00:00 EST 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/728/1/L12· OSTI ID:21560506

Kanekar, Nissim

We report deep Green Bank Telescope spectroscopy in the redshifted NH{sub 3} (1,1), CS 1-0, and H{sub 2}CO 0{sub 00}-1{sub 01} lines from the z {approx} 0.685 absorber toward B0218+357. The inversion (NH{sub 3}) and rotational (CS, H{sub 2}CO) line frequencies have different dependences on the proton-electron mass ratio {mu}, implying that a comparison between the line redshifts is sensitive to changes in {mu}. A joint three-component fit to the NH{sub 3}, CS, and H{sub 2}CO lines yields [{Delta}{mu}/{mu}] = (-3.5 {+-} 1.2) x 10{sup -7}, from z {approx} 0.685 to today, where the error includes systematic effects from comparing lines from different species and possible frequency-dependent source morphology. Two additional sources of systematic error remain, due to time variability in the source morphology and velocity offsets between nitrogen-bearing and carbon-bearing species. We find no statistically significant ({>=}3{sigma}) evidence for changes in {mu} and obtain the stringent 3{sigma} constraint, [{Delta}{mu}/{mu}] < 3.6 x 10{sup -7}, over 6.2 Gyr; this is the best present limit on temporal changes in {mu} from any technique, and for any look-back time, by a factor {approx}>5.

• OSTI ID: 21560506
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 728; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
AMMONIA
BARYONS
CARBON
COSMIC RADIO SOURCES
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
GALAXIES
HADRONS
HYDRIDES
HYDROGEN COMPOUNDS
LEPTONS
MASS
MORPHOLOGY
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
NUCLEONS
PROTONS
QUASARS
RED SHIFT
SORPTION