last updates

Author: christinawilliams

DP1/300_Science_Demos/303_Galaxies/303_3_Color_selections.ipynb

@@ -10,7 +10,7 @@
    "id": "ab80c8e2-f477-40df-ba82-d1cbbe2b5892",
    "metadata": {},
    "source": [
-    "# 303.3. Color Selections\n",
+    "# 303.3. Color selections\n",
     "\n",
     "<div style=\"max-width:300px; float: left; margin-right: 1em\">\n",
     "\n",
@@ -22,7 +22,7 @@
     "Data Release: <a href=\"https://dp1.lsst.io/\">Data Preview 1</a> <br>\n",
     "Container Size: large <br>\n",
     "LSST Science Pipelines version: r29.2.0 <br>\n",
-    "Last verified to run: 2026-06-08 <br>\n",
+    "Last verified to run: 2026-06-12 <br>\n",
     "Repository: <a href=\"https://github.com/lsst/tutorial-notebooks\">github.com/lsst/tutorial-notebooks</a> <br>"
    ]
   },
@@ -161,7 +161,7 @@
    "id": "e9c07b17-bc81-42e2-991c-0ab3a7d30eb8",
    "metadata": {},
    "source": [
-    "Define a query to retrieve galaxies from the object table using the `extendedness`=1 flag. Search around the center of the field using a 0.2 degree search radius to ensure the candidates are identified within the deepest area of g-band imaging. To further ensure good detections, include the $S/N > 10$ cut on the $i$-band."
+    "Define a query to retrieve galaxies from the object table using the `extendedness`=1 flag. Search around the center of the field using a 0.5 degree search radius to cover the full field. To ensure good detections, include the $S/N > 10$ cut on the $i$-band."
    ]
   },
   {
@@ -317,7 +317,7 @@
     "\n",
     "#### 2.2.1. Fetch spec-z catalog\n",
     "\n",
-    "Use the `astroquery` package's `VizieR` service to retrieve the public catalog. Information on the catalog and its contents can be found in [Garilli et al. 2021](https://ui.adsabs.harvard.edu/abs/2021A%26A...647A.150G/abstract). The [catalog ID to search in `VizieR`](https://ui.adsabs.harvard.edu/abs/2022yCat..36470150G/abstract)</a> can be found on adsabs.harvard.edu in connection to the data release paper. Pull the table of data obtained in the ECDFS as `vandels_cdfs`"
+    "Use the `astroquery` package's `VizieR` service to retrieve the public catalog. Information on the catalog and its contents can be found in [Garilli et al. 2021](https://ui.adsabs.harvard.edu/abs/2021A%26A...647A.150G/abstract). The [catalog ID to search in `VizieR`](https://ui.adsabs.harvard.edu/abs/2022yCat..36470150G/abstract)</a> can be found on adsabs.harvard.edu in connection to the data release paper. VANDELS took data in two extragalactic deep fields. Pull the table of data obtained in the ECDFS as `vandels_cdfs`, which is the first table in the return (index 0)."
    ]
   },
   {
@@ -327,9 +327,9 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "v = Vizier(columns=['**'], catalog=\"J/A+A/647/A150\")\n",
-    "v.ROW_LIMIT = -1\n",
-    "all_tables = v.get_catalogs(\"J/A+A/647/A150\")\n",
+    "vandels_survey = Vizier(columns=['**'], catalog=\"J/A+A/647/A150\")\n",
+    "vandels_survey.ROW_LIMIT = -1\n",
+    "all_tables = vandels_survey.get_catalogs(\"J/A+A/647/A150\")\n",
     "vandels_cdfs = all_tables[0]"
    ]
   },
@@ -360,7 +360,7 @@
    "id": "fe011d0d-4077-402c-be5d-176d23c33439",
    "metadata": {},
    "source": [
-    "#### 2.2.3. Cross-match\n",
+    "#### 2.2.2. Cross-match\n",
     "\n",
     "Perform the LBG selection on the Rubin data, then match to objects with the same coordinates in the VANDELS catalog to see what true high redshift galaxies passed the LBG selection and which failed."
    ]
@@ -576,7 +576,7 @@
    "id": "b2849d83-8780-4a28-8b31-2f52e5365aa0",
    "metadata": {},
    "source": [
-    "> Figure 2: Like Figure 2, except that confirmed galaxies are color coded by g-band flux uncertainty as a proxy for variations in the depth or integration time in the g-band filter imaging. Their unsuccessful selection does not show any trend with image depth (which might be expected if galaxies in shallower imaging have smaller lower limits to the g-r color)."
+    "> Figure 2: Like Figure 1, except that confirmed galaxies are color coded by g-band flux uncertainty as a proxy for variations in the depth or integration time in the g-band filter imaging. Their unsuccessful selection does not show any trend with image depth (which might be expected if galaxies in shallower imaging have smaller lower limits to the g-r color)."
    ]
   },
   {
@@ -641,7 +641,7 @@
    "id": "4e702cae-4406-424f-abec-ec2375cfe0b6",
    "metadata": {},
    "source": [
-    "> Figure 3: A color-color diagram showing g - r vs r - i colors for all Rubin galaxies (gray). The Lyman-break color selection window is shown in black dashed lines. Blue points indicate Rubin galaxies that meet the color criteria for being at high-redshift. Stars and pluses indicate Rubin galaxies that are spectroscopically confirmed by VANDELS to lie at z > 3.5 but do and do not meet the color selection (respectively). Confirmed galaxies are color coded by spectroscopic redshift, and their successful selection does not show any trend with redshift."
+    "> Figure 3: Like Figure 1, except that confirmed galaxies are color coded by spectroscopic redshift, and their successful selection does not show any trend with redshift."
    ]
   },
   {
@@ -651,7 +651,7 @@
    "source": [
     "#### 2.3.4 Interpretation\n",
     "\n",
-    "The color selection identifies a large number of true high-redshift galaxies. A number of confirmed galaxies fall outside the selection window. While the color selection is not designed to be 100% inclusive of high redshift galaxies, it should select a relatively pure sample with few interlopers. Galaxies my reside outside the selection box do not seem to trend with any single property tested in Section 2.3.1-2.3.3, but may be caused by a combination of photometric scatter, variation in depth of the g-band imaging, and that the strength of the g-r color will vary across the redshift selection window. Other effects also contribute: dust attenuation in the galaxy will redden the restframe UV probed by the r-i color and similarly decreasing the brightness of the observed r band flux (thus making the g-r color less robustly constrained). A possible effect from DP1 could also be the known issue of a small fraction of [red-wavelength photon leak in the g-band](https://dp1.lsst.io/products/known_issues_and_subtleties.html#g-band-red-leak-excess-long-wavelength-transmission) which might contaminate the dropout filter with redder-wavelength light from the galaxy. This effect is exacerbated by the higher operating temperature of LSSTComCam during commissioning and is expected to be resolved in DP2 LSSTCam data.\n",
+    "The color selection identifies a large number of true high-redshift galaxies. A number of confirmed galaxies fall outside the selection window. While the color selection is not designed to be 100% inclusive of high redshift galaxies, it should select a relatively pure sample with few interlopers. Galaxies may reside outside the selection box do not seem to trend with any single property tested in Section 2.3.1-2.3.3, but may be caused by a combination of photometric scatter, variation in depth of the g-band imaging, and that the strength of the g-r color will vary across the redshift selection window. Other effects also contribute: dust attenuation in the galaxy will redden the restframe UV probed by the r-i color and similarly decreasing the brightness of the observed r band flux (thus making the g-r color less robustly constrained). A possible effect from DP1 could also be the known issue of a small fraction of [red-wavelength photon leak in the g-band](https://dp1.lsst.io/products/known_issues_and_subtleties.html#g-band-red-leak-excess-long-wavelength-transmission) which might contaminate the dropout filter with redder-wavelength light from the galaxy. This effect is exacerbated by the higher operating temperature of LSSTComCam during commissioning and is expected to be resolved in DP2 LSSTCam data.\n",
     "\n",
     "This exemplifies how photometric selection is statistical in nature. While the physics of the Lyman break creates the strong spectral feature that can be exploited for a simple selection, the photometric noise and intrinsic galaxy variations will scatter the galaxy colors in and out of the selection box.\n"
    ]
@@ -716,16 +716,19 @@
     "        g_r = r_data['g_minus_r'][row_idx]\n",
     "        r_i = r_data['r_minus_i'][row_idx]\n",
     "\n",
-    "        query = f\"\"\"\n",
+    "        cutout_query = f\"\"\"\n",
     "        SELECT lsst_band, access_url\n",
     "        FROM ivoa.ObsCore\n",
     "        WHERE dataproduct_subtype = 'lsst.deep_coadd'\n",
     "        AND obs_collection = 'LSST.DP1'\n",
     "        AND CONTAINS(POINT('ICRS', {ra}, {dec}), s_region) = 1\n",
     "        \"\"\"\n",
-    "        \n",
-    "        coadds = tap_service.search(query).to_table()\n",
-    "        \n",
+    "\n",
+    "        job = tap_service.submit_job(cutout_query)\n",
+    "        job.run()\n",
+    "        job.wait()\n",
+    "        coadds = job.fetch_result().to_table()\n",
+    "\n",
     "        for col_idx, f in enumerate(filters):\n",
     "            ax = axes[row_idx][col_idx]\n",
     "            band_match = coadds[coadds['lsst_band'] == f]\n",
@@ -774,7 +777,7 @@
    "id": "e855ba72-793a-47d1-8871-1ca6faac0246",
    "metadata": {},
    "source": [
-    "Now plot the 4-filter cutouts for the real high redshift galaxies confirmed by VANDELS that were identified correctly in the Rubin color selection. "
+    "Now plot the 4-filter cutouts for a few (5) real high redshift galaxies confirmed by VANDELS that were identified correctly in the Rubin color selection. "
    ]
   },
   {
@@ -904,8 +907,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "failed_lbg_indices = np.where(matched_v_all['zsp'][is_selected_lbg] < 3.2)[0]\n",
-    "failed_spec_z = matched_v_all['zsp'][failed_lbg_indices]\n",
+    "failed_spec_z = selected_spec_z[selected_spec_z < 3.2]\n",
     "\n",
     "print(\"Among the VANDELS spectroscopic sample:\")\n",
     "print(f\"{len(selected_spec_z)} out of {len(matched_v_all['zsp'])} are color selected\")\n",