<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<div class="moz-cite-prefix">Dear Ian, all,</div>
<div class="moz-cite-prefix">A small question on one point.<br>
</div>
<div class="moz-cite-prefix">Le 04/02/2026 à 20:38, Dr. Ian N. Evans
a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:D87B478A-C4D8-4BCC-9A47-5F193B34747C@cfa.harvard.edu">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
Dear Francois,
<div><br>
</div>
<div>I consider the arf, rmf, and psf to be response-function data
products.</div>
</blockquote>
OK<br>
<blockquote type="cite"
cite="mid:D87B478A-C4D8-4BCC-9A47-5F193B34747C@cfa.harvard.edu">
<div> Background images and pixel masks are not response-function
data products - they are determined directly from the
observation event list similarly to a total counts image. Bad
pixel is a region data product, but it’s something of a gray
area since it’s a combination of known bad pixel regions plus
bad pixel regions derived directly from the observation event
list.</div>
</blockquote>
<p>In that case what could be the "semantics" term for those in case
of DataLink access : auxiliary ? They are not summarized in table
5.1.5 of the draft<br>
</p>
<p>Cheers</p>
<p>François<br>
</p>
<blockquote type="cite"
cite="mid:D87B478A-C4D8-4BCC-9A47-5F193B34747C@cfa.harvard.edu">
<div><br>
</div>
<div>For the Chandra Source Catalog (CSC) prototype, at least
initially we plan to expose all of the data products directly to
demonstrate that the extension provides the flexibility that we
need. However in production, we likely would not expose all of
the data products individually but rather combine some of them
with the event lists as event bundles (at least for the
individual observation full-field data product set). We would
want to expose the individual observation event lists
individually, but might choose for example to construct an event
bundle that exposes (at least) the event list, bad pixel
regions, aspect histogram, and possible aspect solution as a
bundle since there is very little use for the latter 3 types of
data product without the event list.</div>
<div><br>
</div>
<div>While tying associated and derived data products to an event
list in an event bundle seems sensible for individual
observations, our experience is that this isn’t appropriate for
the CSC advanced data products. Since CSC 2.0 was released we
have had millions of catalog data product downloads and surveyed
our user base as to data product usage.</div>
<div><br>
</div>
<div>The typical usage patterns for the CSC advanced data products
are different from the typical usage patterns for individual
X-ray observation data.</div>
<div><br>
</div>
<div>For the latter the user typically downloads the event list
and ancillary data products (such as responses or other data
products that can be used to build responses) as a set, and then
performs data analysis steps directly on the event list using
the ancillary data products, often after applying
spatial/spectral/temporal filters to the data. Event bundles
facilitate this usage.</div>
<div><br>
</div>
<div>For the CSC advanced data products the usage patterns are
quite different. Many (most) of these advanced data products
are derived from multiple (in some cases hundreds) observations.
Typically the users aren’t interested in performing data
analysis steps on the event lists themselves, and often aren’t
interested in knowing which observation(s) they are derived from
(at least not from the perspective of having to perform a data
query). They just want (e.g.) all the spectra (or light curves,
or photometry MPDFs, or ...) in a certain region of the sky, or
in a given time range, etc. And given the data volume that’s
all they want. Maybe they’ll come back later and ask for a
subset of additional data products after they’ve performed some
preliminary analyses on those data products, but they don’t want
those up front.</div>
<div><br>
</div>
<div>
<div>Based on these usage patterns, I think we will likely want
to expose the remaining CSC data products individually.</div>
</div>
<div><br>
</div>
<div>Thanks,</div>
<div>—Ian</div>
<div>
<div><br>
<blockquote type="cite">
<div>On Jan 27, 2026, at 09:52, BONNAREL FRANCOIS gmail via
heig <a class="moz-txt-link-rfc2396E" href="mailto:heig@ivoa.net"><heig@ivoa.net></a> wrote:</div>
<br class="Apple-interchange-newline">
<div>
<meta http-equiv="content-type"
content="text/html; charset=UTF-8">
<div>
<p>Dear all,</p>
<p>After the meeting last week, I was still thinking
about what the Chandra prototype could look like</p>
<p>For the Paris HESS prototype, I get the idea since a
couple of years now. <br>
</p>
<p>Trying to understand what the CSC data products could
be I came back to Ian's Malta interop presentation.</p>
<p>I copy/paste here one of the slides where some of
these products are described.</p>
<p>Before trying to define dataproduct_type vocabulary
terms for those products I am wondering if we really
need to expose all this data directly in</p>
<p>an ObsTAP service.</p>
<p>For example background images, psf, pixel mask, bad
pixel regions, ARF belong to the "response functions"
category if I'm not mistaking. <br>
</p>
<p>They probably are attached to a photon event list or
an image or ....</p>
<p>Including all this in the main ObsCore table will
overload it very heterogeneously. Some of these
response functions will be similar to what we get in
other domains (psf) some will be very different and
specific to Xray.</p>
<p>I understood that the spatial, spectral, time
characterization of these specific products could be
borrowed from the observation they are associated
with. It's ok but is that useful ?</p>
<p>For accessing these response functions I can imagine
4 solutions which all will have the advantage to let
the OBsTAp service be focused on measurements obtained
from the sky at whatever calib level.</p>
<p> 1 ) the photon event list and response functions
are gathered together in the same tar or archive file
(or MEF) which is typed as an event-bundle. Direct
access to this bundle from Obstap access_url is then
easy. It's the client task to figure out what to do
with the content of the bundle.</p>
<p> 2 ) the various response material is kept as a set
of individual products. All are associated to an event
list or an image or a spectrum. In that case ObsTAP
point to a datalink response which lists all these
different products. The semantics FIELD writes
calibration or response function. Content_qalifier
FIELD writes the very nature of the product.</p>
<p> 3 ) the DataLink reponse content may be organized
as a TAP table. It's then possible to query at the
same time the ObsTAP table and the DataLink-like
table by a join on
ObsCore/obs_publisher_did-DataLink/ID</p>
<p> 4 ) if we need a more detailed description of the
response products to help discover and select them we
could imagine creating a specific "response product"
table following a specific datamodel as proposed by
Mireille in her Gorlitz presentation. This will allow
to attach specific eg :</p>
<p> - time range to a psf or</p>
<p> - specific release date and description to an
arf or a bad pixel map</p>
<p> -.... <br>
</p>
<p> Natural join on obs_publisher_did in both
tables will allow to query those table at the same
time with selection criteria from both.<br>
</p>
<p> Cheers</p>
<p>François<br>
</p>
<p> <br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><span id="cid:part1.601HUn9S.HmZf1KQZ@gmail.com"><ulnvpjC4zXtPT0zn.png></span></p>
</div>
-- <br>
heig mailing list<br>
<a class="moz-txt-link-abbreviated" href="mailto:heig@ivoa.net">heig@ivoa.net</a><br>
<a class="moz-txt-link-freetext" href="https://www.google.com/url?q=http://mail.ivoa.net/mailman/listinfo/heig&source=gmail-imap&ust=1770130364000000&usg=AOvVaw1NuTRL3a6Ib8NM2g8f0TM8">https://www.google.com/url?q=http://mail.ivoa.net/mailman/listinfo/heig&source=gmail-imap&ust=1770130364000000&usg=AOvVaw1NuTRL3a6Ib8NM2g8f0TM8</a><br>
</div>
</blockquote>
</div>
<br>
<div>
<meta charset="UTF-8">
<div
style="font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt;"><span
style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Arial; font-size: 9.5pt; font-style: normal; font-variant-caps: normal; font-weight: 700; letter-spacing: normal; text-transform: none; white-space: pre-wrap; word-spacing: 0px; text-decoration: none; -webkit-text-stroke-width: 0px; font-variant-ligatures: normal; font-variant-east-asian: normal; font-variant-position: normal; vertical-align: baseline;">—</span></div>
<div
style="font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt;"><span
style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Arial; font-size: 9.5pt; font-style: normal; font-variant-caps: normal; font-weight: 700; letter-spacing: normal; text-transform: none; white-space: pre-wrap; word-spacing: 0px; text-decoration: none; -webkit-text-stroke-width: 0px; font-variant-ligatures: normal; font-variant-east-asian: normal; font-variant-position: normal; vertical-align: baseline;">
Dr. Ian Evans</span></div>
<div
style="font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt;"><font
face="Arial"><span
style="font-size: 12.666666984558105px; white-space: pre-wrap;"><b>Astrophysicist</b></span></font></div>
<div
style="font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt;"><font
face="Arial"><span
style="font-size: 12.666666984558105px; white-space: pre-wrap;"><b>Chandra X-ray Center</b></span></font></div>
<div
style="font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); font-family: -webkit-standard; line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt;"><span
style="font-size: 9.5pt; font-family: Arial; background-color: rgb(255, 255, 255); font-weight: 700; font-variant-ligatures: normal; font-variant-east-asian: normal; font-variant-position: normal; vertical-align: baseline; white-space: pre-wrap;">Center for Astrophysics | Harvard & Smithsonian</span></div>
<div
style="font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); font-family: -webkit-standard; line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt;"><span
style="font-size: 9.5pt; font-family: Arial; font-variant-ligatures: normal; font-variant-east-asian: normal; font-variant-position: normal; vertical-align: baseline; white-space: pre-wrap;">
</span></div>
<div
style="font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); font-family: -webkit-standard; line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt;"><span
style="font-size: 9.5pt; font-family: Arial; font-variant-ligatures: normal; font-variant-east-asian: normal; font-variant-position: normal; vertical-align: baseline; white-space: pre-wrap;">Office: (617) 496 7846 | Cell: (617) 699 5152</span></div>
<div
style="font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); font-family: -webkit-standard; line-height: 1.2; margin-top: 0pt; margin-bottom: 0pt;"><span
style="font-family: Arial; font-size: 9.5pt; white-space: pre-wrap;">60 Garden Street | MS 81 | Cambridge, MA 02138</span></div>
<br class="Apple-interchange-newline"
style="font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<span
style="font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);"><span><span><span><span><span><span><span><span><span><span><span><span><span
style="color: rgb(0, 0, 0); font-family: Monaco; font-size: 12px; font-weight: normal; font-style: normal;"><span><span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span><span><img
alt="PastedGraphic-2.png"
src="cid:part1.CyUqxXnU.wz5Eld6v@gmail.com" class=""
width="263"></span>
<meta charset="UTF-8">
<span
style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;"><br
class="Apple-interchange-newline">
<span
style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;"><br>
</span></span>
<div
style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;"><span
style="caret-color: rgb(0, 0, 0); font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><span
style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;"> </span><span
style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><span><span><span><span><span><span><span><span><span><span><span><span
style="color: rgb(0, 0, 0); font-family: Monaco; font-size: 12px; font-weight: normal; font-style: normal;"><span><span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></div>
<span><img alt="PastedGraphic-3.png"
src="cid:part2.DePBnNTD.DE1WFPSA@gmail.com" class=""
width="111"></span>
<meta charset="UTF-8">
<u
style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Monaco; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;"><span
style="font-size: 9.5pt; line-height: 14.566667556762695px; font-family: Arial, sans-serif;"
lang="EN"><a href="http://cfa.harvard.edu/"
moz-do-not-send="true"><br
class="Apple-interchange-newline">
<br class="Apple-interchange-newline">
</a></span></u><font
style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;"
size="2" face="Arial"><u
style="caret-color: rgb(0, 0, 0); font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><span
style="line-height: 14.566667556762695px;" lang="EN"><a
href="http://cfa.harvard.edu/" moz-do-not-send="true">cfa.harvard.edu</a></span></u><span
style="caret-color: rgb(0, 0, 0); font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; line-height: 14.566667556762695px;"
lang="EN"> | <u><a href="http://cfa.harvard.edu/facebook"
moz-do-not-send="true">Facebook</a></u> | <u><a
href="http://cfa.harvard.edu/twitter"
moz-do-not-send="true">Twitter</a></u> | <u><a
href="http://cfa.harvard.edu/youtube"
moz-do-not-send="true">YouTube</a></u></span><span
style="caret-color: rgb(0, 0, 0); font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; line-height: 14.566667556762695px;"
lang="EN"> | <u><a
href="http://cfa.harvard.edu/newsletter"
moz-do-not-send="true">Newsletter</a></u></span></font>
</div>
<br>
</div>
</blockquote>
<p><br>
</p>
</body>
</html>