Commit 526d8e92 authored by Mohammad Akhlaghi's avatar Mohammad Akhlaghi
Browse files

A description is written for the process and results

A first draft of a description has been written to explain the
process.  Since the F814W results are so significantly
offset/different, a cutout was also included as PDF in the paper to
display the possible cause.
parent 3ccbc979
......@@ -26,16 +26,15 @@
%% Set the two column structure and build the title.
%% \begin{@twocolumnfalse}
%% {\setstretch{1.0}
%% \maketitle
%% }
%% \end{@twocolumnfalse}
%% With the ulem package, marked text will be broken into separate
%% lines. However, it will also cause the `\emph' command to underline
......@@ -43,7 +42,74 @@
%% will behave normally.
As described in \citet{bacon15}, the MUSE spectral range covers
multiple HST, ACS-WFC broad-band filters. Therefore, comparing
synthesized broad-band images from the original MUSE datacube with HST
images can be a good measure on the fidelity of the spectrophotometric
calibration. In this section, a similar comparison for the UDF-Mosaic
and UDF-10 fields is discussed. The HST images are first degraded to
have the same PSF as MUSE and then scaled to the MUSE pixel
The HST PSF is derived from the image of one star in the Hubble UDF
field, that has been warped to a grid where its flux-weighted center
is on the center of a pixel. The star was chosen to not be too bright
or too faint \tonote{We can use the average of multiple centered stars
for better accuracy}. For this analysis we used the publicly
available processed images of the XDF survey \citep{XDFsurvey}. The
MUSE PSF is generated from the parametric wavelength-dependent Moffat
fits derived during the MUSE processing (see Section 4) over each of
the 10 subfields (see Figure 1). Each subfield was thus cutout from
the F606W, F775W, F814W, and F850LP images of the XDF survey and
degraded to match the MUSE PSF and pixel-scale.
\noisechisel{} \citep{noisechisel} was then run on the degraded HST
image to define ``clump''s over each given region/filter. The limits
of clumps are defined by noise fluctuations, so the diffuse flux of
objects does not harm this analysis. The clump segmentation map was
then fed into \makecatalog{} with the MUSE and degraded HST images to
generate the catalog. Since the purpose of this study is calibration,
the Sky was artifically set to 0 for the MUSE images.
The resulting plots for the UDF field (combined from all 9 subfields)
can be seen in Figures \ref{udff606w} to \ref{udff850lp} and those for
the deep UDF-10 field are shown in Figures \ref{udf10f606w} to
\ref{udf10f850lp}. The UDF-10 and mosiac magnitudes mostly agree with
each other. The F606W plot is mostly similar to a similar plot in the
HDFS field, see Figure 10 in \citet{bacon15}. \tonote{The results from
F775W and F850LP images are also consistent, but the F814W image is
very strange: the HST magnitudes get much larger for fainter objects
than the MUSE magnitudes. Exactly the same scripts have been used in
all the steps for all the filters, so it is surprizing for me why
only the F814W image shows this strange behavior. }
\tonote{Looking at the degraded and HST images (Figure
\ref{f814w-demo}), I feel that the HST images for the F814W image in
the XDF survey have very bad sky residuals. Currently I feel that
this strong residual is the cause of this offset that is unique to
this filter. But if you have any ideas or suggestions for futher
tests, please let me know to try them out.}
\caption{\label{f814w-demo}Comparison of degraded HST F814W (left)
and F850LP (right) images from UDF-1. The displayed dynamic range
of both images are the same, so white and black correspond to the
same flux values in both images. It is clear that the Sky value in
F814W is systematically larger. This bad Sky subtraction which is
only so significant in F814W can be one cause of the offset in
Figures \ref{udff814w} and \ref{udf10f814w}. }
......@@ -71,7 +137,7 @@
\caption{\label{udf814w} UDF F814W comparison}
\caption{\label{udff814w} UDF F814W comparison}
......@@ -127,6 +193,4 @@
\caption{\label{udf10f850lp} UDF10 F850LP comparison}
......@@ -83,7 +83,7 @@ description.bbl: tex/ref.tex tex/pipeline.tex | tikz
# `tex/*' will not detect it necessarily because it might not be
# present (it is a target to be built by Make).
description.pdf: description.tex tex/* tex/pipeline.tex description.bbl \
$(two-d-hists) | tikz
$(two-d-hists) $(deghst-demo) | tikz
# Delete some outputs for TeX to rebuild (if needed)
# rm tikz/description-figure0*
......@@ -182,3 +182,16 @@ $(muse-corr): $(cutdir)/%-m.fits: $(mcutdir)/%.fits $(cutdir)/%-h.fits
printf("--section=%s,%s", x, y)}'); \
astimgcrop $< $$so -o$@; \
# Crop degraded HST for demo
# --------------------------
# Crops from the HST images for a demonstration of bad F814W results.
h814demodir = $(BDIR)/tex/f814w-demo
deghst-demo = $(h814demodir)/udf1-f814w.pdf $(h814demodir)/udf1-f850lp.pdf
$(deghst-demo): $(h814demodir)/%.pdf: $(cutdir)/%-h.fits | $(h814demodir)
astconvertt $< -o$@ --fluxlow=-0.001 --fluxhigh=0.02 --noinvert
\node[anchor=south west] (img) at (0,0)
{\includegraphics[width=0.49\linewidth] {\inputdir/udf1-f814w.pdf}};
\node[anchor=south west] (img) at (0.5\linewidth,0)
{\includegraphics[width=0.49\linewidth] {\inputdir/udf1-f850lp.pdf}};
......@@ -20,6 +20,38 @@ archivePrefix = "arXiv",
author = {{Bacon}, R. and {Brinchmann}, J. and {Richard}, J. and {Contini}, T. and
{Drake}, A. and {Franx}, M. and {Tacchella}, S. and {Vernet}, J. and
{Wisotzki}, L. and {Blaizot}, J. and {Bouch{\'e}}, N. and {Bouwens}, R. and
{Cantalupo}, S. and {Carollo}, C.~M. and {Carton}, D. and {Caruana}, J. and
{Cl{\'e}ment}, B. and {Dreizler}, S. and {Epinat}, B. and {Guiderdoni}, B. and
{Herenz}, C. and {Husser}, T.-O. and {Kamann}, S. and {Kerutt}, J. and
{Kollatschny}, W. and {Krajnovic}, D. and {Lilly}, S. and {Martinsson}, T. and
{Michel-Dansac}, L. and {Patricio}, V. and {Schaye}, J. and
{Shirazi}, M. and {Soto}, K. and {Soucail}, G. and {Steinmetz}, M. and
{Urrutia}, T. and {Weilbacher}, P. and {de Zeeuw}, T.},
title = "{The MUSE 3D view of the Hubble Deep Field South}",
journal = {\aap},
archivePrefix = "arXiv",
eprint = {1411.7667},
keywords = {cosmology: observations, galaxies: evolution, galaxies: high-redshift, techniques: imaging spectroscopy, galaxies: formation},
year = 2015,
month = mar,
volume = 575,
eid = {A75},
pages = {A75},
doi = {10.1051/0004-6361/201425419},
adsurl = {\%26A...575A..75B},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
author = {{Illingworth}, G.~D. and {Magee}, D. and {Oesch}, P.~A. and
{Bouwens}, R.~J. and {Labb{\'e}}, I. and {Stiavelli}, M. and
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