From ff324609f77c1bc357060e77e48b13c4cd728e6d Mon Sep 17 00:00:00 2001 From: "Grzegorz (Greg) Madejski" <36776103+Madejski@users.noreply.github.com> Date: Wed, 20 Nov 2024 15:08:21 -0800 Subject: [PATCH] Update portal-intro.rst --- data-access-analysis-tools/portal-intro.rst | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/data-access-analysis-tools/portal-intro.rst b/data-access-analysis-tools/portal-intro.rst index 702ce45a..d8db61e4 100644 --- a/data-access-analysis-tools/portal-intro.rst +++ b/data-access-analysis-tools/portal-intro.rst @@ -20,17 +20,20 @@ How to extract and plot forced photometry light curve The Rubin data set readily provides fluxes of the objects when they were detected at a ``SNR > 5``. In some cases, the science goal on-hand requires lower-SNR measurements. -This might be the case when fluxes of a given object measured during all visits to its location are required, for instance a measurement of a source flux before and after a flare or explosion. +This might be the case when fluxes of a given object measured during all visits to its location are required, for instance a measurement of its flux before and after a flare or explosion. In those cases, the forced photometry - available in the ``ForcedSourceOnDiaObject`` table - has to be used instead. That table contains "forced" flux measurements in locations of all objects which had positive ``SNR > 5`` detections in a table ``dp02_dc2_catalogs.DiaObject``. The table ``dp02_dc2_catalogs.DiaObject``, in turn, contains objects which were detected using the "Difference Image Analysis" (DIA) method. The DIA method basically subtracts the fluxes of the previously undetected objects from those that showed ``SNR > 5`` detections in individual single-epoch difference images. -This tutorial demonstrates how to create a forced photometry lightcurve for the supernova located at (67.4579, -44.0802). +This example demonstrates how to create a forced photometry lightcurve for the supernova located at (67.4579, -44.0802). -Since the - -**1.1.** Log in to the Portal Aspect of the Rubin Science Platform, and select "DP0.2 Catalogs" tab. +Since individual Processed Visit Images might have very slightly different coordinates for the same object. +With this, instead of providing the RA and Dec to the search, it is wise to extract the data from the ``dp02_dc2_catalogs.DiaObject`` table using the object's unique ``diaObjectId``. +Determining the ``diaObjectId`` can be accomplished via the Portal Aspect of the Rubin Science Platform, clicking on the "UI assisted" button, selecting "DP0.2 Catalogs" tab, chosing the "dp02_dc2_catalogs" on the left, and "dp02_dc2_catalogs.DiaObject" table on the right. +Only the spatial constraints need to be entered on the left, with the 67.4579, -44.0802 - and a 2 arcseconds radius using the "cone Shape" ("Temporal" constraints need to be unchecked). +For the "Output Column Selection" only the ``diaObjectId`` needs to be checked. +Pressing the "search" button will return only one ``diaObjectId`` - it is 1252220598734556212. **1.2.** At upper right on the main Portal user interface, click "Edit ADQL" to switch to the ADQL query view. (In the figure below, see the red arrow.)