Model-independent constraints on clustering and growth of cosmic structures from BOSS DR12 galaxies in harmonic space

We present a new, model-independent measurement of the clustering amplitude of galaxies and the growth of cosmic large-scale structures from the Baryon Oscillation Spectroscopic Survey (BOSS) 12th data release (DR12). This is achieved by generalising harmonic-space power spectra for galaxy clustering to measure separately the magnitudes of the density and the redshift-space distortion terms, respectively related to the clustering amplitude of structures, $b\sigma_8(z)$, and their growth, $f\sigma_8(z)$. We adopt a tomographic approach with 15 redshift bins in $z\in[0.15,0.67]$. We restrict our analysis to strictly linear scales, implementing a redshift-dependent maximum multipole for each bin. The measurements do not appear to suffer from systematic effects and show excellent agreement with the theoretical predictions from the Planck cosmic microwave background analysis assuming a $\Lambda$CDM cosmology. Our results also agree with previous analyses by the BOSS collaboration. Furthermore, our method provides the community with a new tool for data analyses of the cosmic large-scale structure complementary to state-of-the-art approaches in configuration or Fourier space. Amongst its merits, we list: it being more agnostic with respect to the underlying cosmological model; its roots in a well-defined and gauge-invariant observable; the possibility to account naturally for wide-angle effects and even relativistic corrections on ultra-large scales; and the capability to perform an almost arbitrarily fine redshift binning with little computational effort. These aspects are all the more relevant for the oncoming generation of cosmological experiments such as Euclid, the Dark Energy Spectroscopic Instrument (DESI), the Legacy Survey of Space and Time (LSST), and the SKA Project.

I provide three new .bst files to replace the standard L A T E X numerical ones: plainnat.bst abbrvnat.bst unsrtnat.bst

Basic commands
The natbib package has two basic citation commands, \citet and \citep for textual and parenthetical citations, respectively. There also exist the starred versions \citet* and \citep* that print the full author list, and not just the abbreviated one. All of these may take one or two optional arguments to add some text before and after the citation.

Numerical mode
These examples are for author-year citation mode. In numerical mode, the results are different.

Suppressed parentheses
As an alternative form of citation, \citealt is the same as \citet but without parentheses. Similarly, \citealp is \citep without parentheses. Multiple references, notes, and the starred variants also exist. The \citetext command allows arbitrary text to be placed in the current citation parentheses. This may be used in combination with \citealp.

Forcing upper cased names
If the first author's name contains a von part, such as "della Robbia", then \citet{dRob98} produces "della Robbia (1998)", even at the beginning of a sentence. One can force the first letter to be in upper case with the command \Citet instead. Other upper case commands also exist.
These commands also exist in starred versions for full author names.

Citation aliasing
Sometimes one wants to refer to a reference with a special designation, rather than by the authors, i.e. as Paper I, Paper II. Such aliases can be defined and used, textual and/or parenthetical with: ⇒ (Paper I) These citation commands function much like \citet and \citep: they may take multiple keys in the argument, may contain notes, and are marked as hyperlinks.

Selecting citation style and punctuation
Use the command \bibpunct with one optional and 6 mandatory arguments: 1. the opening bracket symbol, default = ( 2. the closing bracket symbol, default = ) 3. the punctuation between multiple citations, default = ; 4. the letter 'n' for numerical style, or 's' for numerical superscript style, any other letter for author-year, default = author-year; 5. the punctuation that comes between the author names and the year 6. the punctuation that comes between years or numbers when common author lists are suppressed (default = ,); The optional argument is the character preceding a post-note, default is a comma plus space. In redefining this character, one must include a space if one is wanted.

Other formatting options
Redefine \bibsection to the desired sectioning command for introducing the list of references. This is normally \section* or \chapter*.
Define \bibpreamble to be any text that is to be printed after the heading but before the actual list of references.
Define \bibfont to be a font declaration, e.g. \small to apply to the list of references.
Define \citenumfont to be a font declaration or command like \itshape or \textit.
Redefine \bibnumfmt as a command with an argument to format the numbers in the list of references. The default definition is [#1].
The indentation after the first line of each reference is given by \bibhang; change this with the \setlength command.
The vertical spacing between references is set by \bibsep; change this with the \setlength command.

Automatic indexing of citations
If one wishes to have the citations entered in the .idx indexing file, it is only necessary to issue \citeindextrue at any point in the document. All following \cite commands, of all variations, then insert the corresponding entry to that file. With \citeindexfalse, these entries will no longer be made.

Use with chapterbib package
The natbib package is compatible with the chapterbib package which makes it possible to have several bibliographies in one document.
The package makes use of the \include command, and each \included file has its own bibliography.
The order in which the chapterbib and natbib packages are loaded is unimportant.
The chapterbib package provides an option sectionbib that puts the bibliography in a \section* instead of \chapter*, something that makes sense if there is a bibliography in each chapter. This option will not work when natbib is also loaded; instead, add the option to natbib.
Every \included file must contain its own \bibliography command where the bibliography is to appear. The database files listed as arguments to this command can be different in each file, of course. However, what is not so obvious, is that each file must also contain a \bibliographystyle command, preferably with the same style argument.

Sorting and compressing citations
Do not use the cite package with natbib; rather use one of the options sort or sort&compress.
These also work with author-year citations, making multiple citations appear in their order in the reference list.

Long author list on first citation
Use option longnamesfirst to have first citation automatically give the full list of authors.
Suppress this for certain citations with \shortcites{key-list }, given before the first citation.

Local configuration
Any local recoding or definitions can be put in natbib.cfg which is read in after the main package file. super for superscripted numerical citations, as in Nature; sort orders multiple citations into the sequence in which they appear in the list of references; sort&compress as sort but in addition multiple numerical citations are compressed if possible (as 3-6, 15); longnamesfirst makes the first citation of any reference the equivalent of the starred variant (full author list) and subsequent citations normal (abbreviated list); sectionbib redefines \thebibliography to issue \section* instead of \chapter*; valid only for classes with a \chapter command; to be used with the chapterbib package; nonamebreak keeps all the authors' names in a citation on one line; causes overfull hboxes but helps with some hyperref problems.