C-Band All-Sky Survey: a first look at the Galaxy

Irfan, Melis O.; Dickinson, C.; Davies, R. D.; Copley, Charles; Davis, R. J.; Ferreira, Pedro G.; Holler, C. M.; Jonas, J. L.; Jones, Michael E.; King, O. G.; Leahy, J. P.; Leech, J.; Leitch, E. M.; Muchovej, Stephen; Pearson, T. J.; Peel, M.; Readhead, A. C. S.; Stevenson, M. A.; Sutton, D.; Taylor, Angela C.; Zuntz, Joe

doi:10.1093/mnras/stv212

Cited by 34 publications

(72 citation statements)

References 61 publications

(64 reference statements)

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“…Further model-dependent studies and data from MHz to tens of GHz, including the Square Kilometre Array telescope (e.g. Dickinson et al 2015) and C-BASS (Irfan et al 2015) will help in separating the components and may provide more stringent constraints to the all-electron spectrum. Future observations could also help in explaining the isotropic radio excess seen for example by ARCADE 2 (Singal et al 2011).…”

Section: Implications On the Results From Possible Additional Uncertamentioning

confidence: 99%

Imprints of cosmic rays in multifrequency observations of the interstellar emission

Orlando

2017

Monthly Notices of the Royal Astronomical Society

102

147

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Ever since the discovery of Cosmic Rays (CRs), significant advancements have been made in modeling their propagation in the Galaxy and in the Heliosphere. However, propagation models suffer from degeneracy of many parameters. To complicate the picture the precision of recent data have started challenging existing models.To tackle these issues we use available multifrequency observations of the interstellar emission from radio to gamma rays, together with direct CR measurements, to study local interstellar spectra (LIS) and propagation models. As a result, the electron LIS is characterized without any assumption on solar modulation, and favorite propagation models are put forward. More precisely, our analysis leads to the following main conclusions: (1) the electron injection spectrum needs at least a break below a few GeV; (2) even though consistent with direct CR measurements, propagation models producing a LIS with large all-electron density from a few hundreds of MeV to a few GeV are disfavored by both radio and gamma-ray observations; (3) the usual assumption that direct CR measurements, after accounting for solar modulation, are representative of the proton LIS in our ∼1 kpc region is challenged by the observed local gamma-ray HI emissivity. We provide the resulting proton LIS, all-electron LIS, and propagation parameters, based on synchrotron, gamma-ray, and direct CR data. A plain diffusion model and a tentative diffusive-reacceleration model are put forward. The various models are investigated in the inner-Galaxy region in X-rays and gamma rays. Predictions of the interstellar emission for future gamma-ray instruments (e-ASTROGAM and AMEGO) are derived.

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Section: Implications On the Results From Possible Additional Uncertamentioning

confidence: 99%

Imprints of cosmic rays in multifrequency observations of the interstellar emission

Orlando

2017

Monthly Notices of the Royal Astronomical Society

102

147

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“…This is a relatively rigid parameterization, but the AME is not a dominant source of error in the forecast and we find that expanding the model does not significantly change the results. We furthermore anticipate that future ground-based observations will help to improve the modeling of this component, given its potential relevance to ongoing and planned B-mode searches (Irfan et al 2015;Génova-Santos et al 2015).…”

Section: Foreground Modelingmentioning

confidence: 99%

“…Unless stated otherwise, we impose a 10% prior on the synchrotron amplitude and spectral index throughout the forecasting to represent the use of external datasets such as the Haslam 408 MHz map, WMAP, Planck, C-BASS, QUIJOTE, or future observations (Haslam et al 1981(Haslam et al , 1982Remazeilles et al 2015;Bennett et al 2013;Planck Collaboration et al 2016;Irfan et al 2015;Génova-Santos et al 2015). We find that in particular future low-frequency ( 15 − 30 GHz) observations that can constrain the synchrotron SED or limit its contribution using spatial information to better than 1% will be very valuable for tightening the constraints on µ.…”

Section: Foreground Modelingmentioning

confidence: 99%

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Abitbol

Chluba

Hill

et al. 2017

Monthly Notices of the Royal Astronomical Society

146

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Measurements of cosmic microwave background spectral distortions have profound implications for our understanding of physical processes taking place over a vast window in cosmological history. Foreground contamination is unavoidable in such measurements and detailed signal-foreground separation will be necessary to extract cosmological science. In this paper, we present MCMC-based spectral distortion detection forecasts in the presence of Galactic and extragalactic foregrounds for a range of possible experimental configurations, focusing on the Primordial Inflation Explorer (PIXIE) as a fiducial concept. We consider modifications to the baseline PIXIE mission (operating 12 months in distortion mode), searching for optimal configurations using a Fisher approach. Using only spectral information, we forecast an extended PIXIE mission to detect the expected average non-relativistic and relativistic thermal Sunyaev-Zeldovich distortions at high significance (194σ and 11σ, respectively), even in the presence of foregrounds. The ΛCDM Silk damping µ-type distortion is not detected without additional modifications of the instrument or external data. Galactic synchrotron radiation is the most problematic source of contamination in this respect, an issue that could be mitigated by combining PIXIE data with future ground-based observations at low frequencies (ν 15 − 30 GHz). Assuming moderate external information on the synchrotron spectrum, we project an upper limit of |µ| < 3.6 × 10 −7 (95% c.l.), slightly more than one order of magnitude above the fiducial ΛCDM signal from the damping of small-scale primordial fluctuations, but a factor of 250 improvement over the current upper limit from COBE/FIRAS. This limit could be further reduced to |µ| < 9.4 × 10 −8 (95% c.l.) with more optimistic assumptions about extra low-frequency information and would rule out many alternative inflation models as well as provide new constraints on decaying particle scenarios.

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“…That makes WMAP unsuitable for the analysis of most Galactic SNRs (see Green 2014). Only a few Galactic SNRs, with large enough angular dimensions were detected with WMAP (Cas A, Puppis A, HB 21, W44 region; Weiland et al 2011;Hewitt et al 2012;Pivato et al 2013;Irfan et al 2015;Génova-Santos et al 2016).…”

Section: Introductionmentioning

confidence: 99%

A New Look at the Integrated Radio/Microwave Continuum Spectrum of Galactic Supernova Remnant Ic 443

Onić¹,

Urošević²,

Leahy³

2016

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Recent observations of the microwave sky, by the space telescopes such as WMAP and Planck, have opened a new window into the analysis of continuum emission from supernova remnants (SNRs). In this paper, different emission models that can explain the characteristic shape of presently known integrated radio/microwave continuum spectrum of the Galactic SNR IC 443 are tested and discussed. In particular, the possibility that the slight bump in the integrated continuum of this remnant around 20 -70 GHz is genuine and that can be explained by the contribution of additional emission mechanism such as of spinning dust is emphasized. We find that adding a spinning dust component to the emission model improves the fit of the integrated spectrum of this SNR while, at the same time preserves the physically probable parameter values. Finally, models that include the high-frequency synchrotron bending of the IC 443 radio to microwave continuum are favored.

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C-Band All-Sky Survey: a first look at the Galaxy

Cited by 34 publications

References 61 publications

Imprints of cosmic rays in multifrequency observations of the interstellar emission

Imprints of cosmic rays in multifrequency observations of the interstellar emission

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

A New Look at the Integrated Radio/Microwave Continuum Spectrum of Galactic Supernova Remnant Ic 443

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