GRBs as standard candles: There is no "circularity problem" (and there never was)

Details GRBs as standard candles: There is no "circularity problem" (and there never was) GRBs as standard candles: There is no "circularity problem" (and there never was)

2010-02-18

arxiv.org/abs/1002.3434v2

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

10 pages, to appear in New Astronomy

Scientific paper

10.1016/j.newast.2010.08.001

The 2002 discovery of the "Amati Relation" of GRB spectra created the possibility that this and other correlations of GRB phenomenology might be used to make GRBs into standard candles. One recurring apparent difficulty with this program has been that some of the primary observational quantities to be fit as "data" - the isotropic-equivalent prompt energy $E_{iso}$ and the collimation-corrected "total" prompt energy energy $E_{\gamma}$ - depend for their construction on the very cosmological models that they are supposed to help constrain. This is the so-called "circularity problem" of standard candle GRBs. This paper is intended to point out that the circularity problem is not in fact a problem at all, except to the extent that it amounts to a self-inflicted wound. It arises essentially because of an unfortunate choice of data variables, such as $E_{iso}$, which are unnecessarily model-dependent. If, instead, the empirical correlations of GRB phenomenology which are formulated in source-variables are {\it mapped to the primitive observational variables} (such as fluence) and compared to the observations in that space, then all circularity disappears. I also indicate here a set of procedures for encoding high-dimensional empirical correlations in a "Gaussian Tube" smeared model that includes both the correlation and its intrinsic scatter, and how that source-variable model may easily be mapped to the space of primitive observables and fashioned into a likelihood. I discuss the projections of such Gaussian tubes into sub-spaces, which may be used to incorporate data from GRB events that may lack some element of the data (for example, GRBs without ascertained jet-break times). In this way, a large set of inhomogeneously observed GRBs may be assimilated into a single analysis, so long as each possesses at least two correlated data attributes.

Affiliated with

Also associated with

No associations

Rating

GRBs as standard candles: There is no "circularity problem" (and there never was) does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with GRBs as standard candles: There is no "circularity problem" (and there never was), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and GRBs as standard candles: There is no "circularity problem" (and there never was) will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-404903