The astro-ph “Reader’s Digest”

Christopher M. Faesi (Harvard Univ.)on behalf of the Astrobites collaboration

AAS 222nd Meeting

Indianapolis, IN

June 4, 2013

astrobites.org

Astrobites

Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results

We present cosmological parameter constraints based on the final nine-year WMAP data, in conjunction with additional cosmological data sets. The WMAP data alone, and in combination, continue to be remarkably well fit by a six-parameter LCDM model. When WMAP data are combined with measurements of the high-l CMB anisotropy, the BAO scale, and the Hubble constant, the densities, Omegabh2, Omegach2, and Omega_L, are each determined to a precision of ~1.5%. The amplitude of the primordial spectrum is measured to within 3%, and there is now evidence for a tilt in the primordial spectrum at the 5sigma level, confirming the first detection of tilt based on the five-year WMAP data. At the end of the WMAP mission, the nine-year data decrease the allowable volume of the six-dimensional LCDM parameter space by a factor of 68,000 relative to pre-WMAP measurements. We investigate a number of data combinations and show that their LCDM parameter fits are consistent. New limits on deviations from the six-parameter model are presented, for example: the fractional contribution of tensor modes is limited to r<0.13 (95% CL); the spatial curvature parameter is limited to -0.0027 (+0.0039/-0.0038); the summed mass of neutrinos is <0.44 eV (95% CL); and the number of relativistic species is found to be 3.84+/-0.40 when the full data are analyzed. The joint constraint on Neff and the primordial helium abundance agrees with the prediction of standard Big Bang nucleosynthesis. We compare recent PLANCK measurements of the Sunyaev-Zel'dovich effect with our seven-year measurements, and show their mutual agreement. Our analysis of the polarization pattern around temperature extrema is updated. This confirms a fundamental prediction of the standard cosmological model and provides a striking illustration of acoustic oscillations and adiabatic initial conditions in the early universe.

G. Hinshaw and the WMAP Team

http://arxiv.org/abs/1212.5226

June 4, 2013222nd AAS Meeting

Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results

We present cosmological parameter constraints based on the final nine-year WMAP data, in conjunction with additional cosmological data sets. The WMAP data alone, and in combination, continue to be remarkably well fit by a six-parameter LCDM model. When WMAP data are combined with measurements of the high-l CMB anisotropy, the BAO scale, and the Hubble constant, the densities, Omegabh2, Omegach2, and Omega_L, are each determined to a precision of ~1.5%. The amplitude of the primordial spectrum is measured to within 3%, and there is now evidence for a tilt in the primordial spectrum at the 5sigma level, confirming the first detection of tilt based on the five-year WMAP data. At the end of the WMAP mission, the nine-year data decrease the allowable volume of the six-dimensional LCDM parameter space by a factor of 68,000 relative to pre-WMAP measurements. We investigate a number of data combinations and show that their LCDM parameter fits are consistent. New limits on deviations from the six-parameter model are presented, for example: the fractional contribution of tensor modes is limited to r<0.13 (95% CL); the spatial curvature parameter is limited to -0.0027 (+0.0039/-0.0038); the summed mass of neutrinos is <0.44 eV (95% CL); and the number of relativistic species is found to be 3.84+/-0.40 when the full data are analyzed. The joint constraint on Neff and the primordial helium abundance agrees with the prediction of standard Big Bang nucleosynthesis. We compare recent PLANCK measurements of the Sunyaev-Zel'dovich effect with our seven-year measurements, and show their mutual agreement. Our analysis of the polarization pattern around temperature extrema is updated. This confirms a fundamental prediction of the standard cosmological model and provides a striking illustration of acoustic oscillations and adiabatic initial conditions in the early universe.

G. Hinshaw and the WMAP Team

http://arxiv.org/abs/1212.5226

Jargon Alert!

June 4, 2013222nd AAS Meeting

Astrobites to the rescue!

Accessible language

Direct link to astro-ph article

Category links

Understandable title

June 4, 2013222nd AAS Meeting

Origins and Mission

The Astrobites Mission:

Inform our readers by summarizing recent astronomy results

Educate students and the public on research methods, terminology, and technical background

Inspire the next generation of scientists

June 4, 2013222nd AAS Meeting

Founded: November 2010 by Nathan Sanders and four other Harvard astronomy graduate students

Who reads Astrobites?

Target audience: Undergraduates with minimal physics background

Actual audience: Students (Grad + Undergrad) Professional astronomers Astronomy enthusiasts Educators

June 4, 2013222nd AAS Meeting

Astrobites reaches more than 500 readers per dayastrobites.org: unique visitors by month: June 2012-May 2013

From Google analyticsNote: 2/3 of our readers access astrobites through email or RSS feeds

US Readers by locationData from Oct./Nov. 2012 survey

Who writes for Astrobites? 26 Graduate student authors

from 17 institutions worldwide

Authors post and edit once each per month

> 700 articles published to date

100% student-run

June 4, 2013222nd AAS Meeting

Astrobites Author Institutions

Beyond the Blog Astrobites as a classroom resource (N.E. Sanders et al.

2012, Astronomy Education Review, 11 (1), 010201) Communicating Science 2013: A workshop for Graduate

students (workshop.astrobites.com) Model for other science ‘bites websites: e.g.

chembites.org

June 4, 2013222nd AAS Meeting

Thanks!June 4, 2013222nd AAS Meeting

astrobites.orgNick Ballering (U. AZ)Aaron Bray (Harvard)Elisa Chisari (Princeton)Ian Czekala (Harvard)Jessica Donaldson (U. MD)Courtney Dressing (Harvard)Maria Drout (Harvard)Chris Faesi (Harvard)Ryan Foltz (UC Riverside)Josh Fuchs (UNC Chapel Hill)Dan Gifford (U. MI)Nathan Goldbaum (UCSC)Shannon Hall (U. WY)Nick Hand (UC Berkeley)Kirit Karkare (Harvard)

Michelle Kislak (UCLA)Susanna Kohler (U. CO Boulder)Tanmoy Laskar (Harvard)Elizabeth Lovegrove (UCSC)Betsy Mills (UCLA)Ben Montet (Caltech)Kevin Moore (UC Santa Barbara)Lucia Morganti (MPE Garching)Caroline Morley (UCSC)Erika Nesvold (U. MD)Elisabeth Newton (Harvard)Joe O’Rourke (Caltech)Alice Olmstead (U. MD)Tony Pan (Harvard)

Kim Phifer (UCLA)Adele Plunkett (Yale/U. Chile)Sukrit Ranjan (Harvard)Anna Rosen (UCSC)Katherine Rosenfeld (Harvard)Nathan Sanders (Harvard)Evan Schneider (U. AZ)Zack Slepian (Harvard)Allison Strom (Caltech)Josh Suresh (Harvard)Justin Vasel (U. MN Duluth)Lauren Weiss (UC Berkeley)