From 22cd113b8fb86923545937ae4d6869cf2890112d Mon Sep 17 00:00:00 2001
From: Andre Offringa <offringa@astron.nl>
Date: Thu, 13 Jul 2023 09:54:49 +0000
Subject: [PATCH] Implement a circular beam for MeerKAT (L-band)
---
CMakeLists.txt | 2 +-
README.md | 3 +-
cpp/CMakeLists.txt | 1 +
cpp/circularsymmetric/CMakeLists.txt | 4 +-
cpp/circularsymmetric/meerkatcoefficients.cc | 10 +++++
cpp/circularsymmetric/meerkatcoefficients.h | 45 ++++++++++++++++++++
cpp/load.cc | 12 +++++-
cpp/load.h | 1 +
8 files changed, 72 insertions(+), 6 deletions(-)
create mode 100644 cpp/circularsymmetric/meerkatcoefficients.cc
create mode 100644 cpp/circularsymmetric/meerkatcoefficients.h
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 89114c6f..dab55fea 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,7 +7,7 @@ cmake_minimum_required(VERSION 3.8)
#------------------------------------------------------------------------------
# Set version name and project number
-set(EVERYBEAM_VERSION 0.5.1)
+set(EVERYBEAM_VERSION 0.5.2)
if(EVERYBEAM_VERSION MATCHES "^([0-9]+)\\.([0-9]+)\\.([0-9]+)")
set(EVERYBEAM_VERSION_MAJOR "${CMAKE_MATCH_1}")
set(EVERYBEAM_VERSION_MINOR "${CMAKE_MATCH_2}")
diff --git a/README.md b/README.md
index c840a0a2..8a61e5b4 100644
--- a/README.md
+++ b/README.md
@@ -7,8 +7,9 @@ radio telescopes, i.e.:
* SKA/OSKAR
* ATCA
* GMRT
-* VLA
+* MeerKAT
* MWA
+* VLA
This package also provides an abstract interface to a selection of beam responses for apperture arrays (LOFAR/OSKAR), and beamformed versions thereof. Currently implemented are:
diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
index 3174a49b..0499c733 100644
--- a/cpp/CMakeLists.txt
+++ b/cpp/CMakeLists.txt
@@ -65,6 +65,7 @@ add_library(
pointresponse/skamidpoint.cc
circularsymmetric/atcacoefficients.cc
circularsymmetric/gmrtcoefficients.cc
+ circularsymmetric/meerkatcoefficients.cc
circularsymmetric/vlacoefficients.cc
circularsymmetric/voltagepattern.cc
# Phased array telescopes (SKA, LOFAR)
diff --git a/cpp/circularsymmetric/CMakeLists.txt b/cpp/circularsymmetric/CMakeLists.txt
index db38a6e4..894a2fa8 100644
--- a/cpp/circularsymmetric/CMakeLists.txt
+++ b/cpp/circularsymmetric/CMakeLists.txt
@@ -1,6 +1,6 @@
# Copyright (C) 2020 ASTRON (Netherlands Institute for Radio Astronomy)
# SPDX-License-Identifier: GPL-3.0-or-later
-install(FILES atcacoefficients.h gmrtcoefficients.h vlacoefficients.h
- voltagepattern.h
+install(FILES atcacoefficients.h gmrtcoefficients.h meerkatcoefficients.h
+ vlacoefficients.h voltagepattern.h
DESTINATION "include/${CMAKE_PROJECT_NAME}/circularsymmetric")
diff --git a/cpp/circularsymmetric/meerkatcoefficients.cc b/cpp/circularsymmetric/meerkatcoefficients.cc
new file mode 100644
index 00000000..e8d31dea
--- /dev/null
+++ b/cpp/circularsymmetric/meerkatcoefficients.cc
@@ -0,0 +1,10 @@
+// Copyright (C) 2023 ASTRON (Netherlands Institute for Radio Astronomy)
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "meerkatcoefficients.h"
+
+namespace everybeam {
+namespace circularsymmetric {
+constexpr std::array<double, 6> MeerKATCoefficients::coefficients_;
+}
+} // namespace everybeam
diff --git a/cpp/circularsymmetric/meerkatcoefficients.h b/cpp/circularsymmetric/meerkatcoefficients.h
new file mode 100644
index 00000000..17ecc353
--- /dev/null
+++ b/cpp/circularsymmetric/meerkatcoefficients.h
@@ -0,0 +1,45 @@
+// Copyright (C) 2023 ASTRON (Netherlands Institute for Radio Astronomy)
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef EVERYBEAM_CIRCULARSYMMETRIC_MEERKAT_COEFFICIENTS_H_
+#define EVERYBEAM_CIRCULARSYMMETRIC_MEERKAT_COEFFICIENTS_H_
+
+#include <array>
+#include <map>
+#include <string>
+
+#include "coefficients.h"
+
+namespace everybeam {
+namespace circularsymmetric {
+class MeerKATCoefficients final : public Coefficients {
+ public:
+ MeerKATCoefficients() {}
+
+ aocommon::UVector<double> GetFrequencies(double frequency) const override {
+ return aocommon::UVector<double>{frequency};
+ }
+ aocommon::UVector<double> GetCoefficients(double frequency) const override {
+ return aocommon::UVector<double>(coefficients_.begin(),
+ coefficients_.end());
+ }
+ double MaxRadiusInArcMin() const override {
+ // This is approximately the place of the first null with these
+ // coefficients.
+ return 71.0;
+ }
+ double ReferenceFrequency() const override { return 1.278e9; }
+ bool AreInverted() const override { return false; }
+
+ private:
+ /**
+ * These coefficients are from "The 1.28 GHz MeerKAT DEEP2 Image" (Mauch et
+ * al. 2020). See https://iopscience.iop.org/article/10.3847/1538-4357/ab5d2d
+ * These are valid for L-band.
+ */
+ static constexpr std::array<double, 6> coefficients_{
+ 1.0, -0.3514e-03, 0.5600e-07, -0.0474e-10, 0.00078e-13, 0.00019e-16};
+};
+} // namespace circularsymmetric
+} // namespace everybeam
+#endif // EVERYBEAM_CIRCULARSYMMETRIC_MEERKAT_COEFFICIENTS_H_
diff --git a/cpp/load.cc b/cpp/load.cc
index b0629c3f..b2e22cb4 100644
--- a/cpp/load.cc
+++ b/cpp/load.cc
@@ -11,6 +11,7 @@
#include "circularsymmetric/atcacoefficients.h"
#include "circularsymmetric/gmrtcoefficients.h"
+#include "circularsymmetric/meerkatcoefficients.h"
#include "circularsymmetric/vlacoefficients.h"
#include <casacore/ms/MeasurementSets/MeasurementSet.h>
@@ -38,6 +39,8 @@ TelescopeType GetTelescopeType(const casacore::MeasurementSet& ms) {
return kGMRTTelescope;
} else if (telescope_name == "LOFAR") {
return kLofarTelescope;
+ } else if (telescope_name == "MEERKAT") {
+ return kMeerKATTelescope;
} else if (telescope_name == "MID") {
return kSkaMidTelescope;
} else if (telescope_name == "MWA") {
@@ -69,8 +72,8 @@ std::unique_ptr<telescope::Telescope> Load(const casacore::MeasurementSet& ms,
telescope =
std::make_unique<telescope::Dish>(ms, std::move(coefs), options);
} break;
- case kVLATelescope: {
- auto coefs = std::make_unique<circularsymmetric::VLACoefficients>("");
+ case kMeerKATTelescope: {
+ auto coefs = std::make_unique<circularsymmetric::MeerKATCoefficients>();
telescope =
std::make_unique<telescope::Dish>(ms, std::move(coefs), options);
} break;
@@ -83,6 +86,11 @@ std::unique_ptr<telescope::Telescope> Load(const casacore::MeasurementSet& ms,
case kSkaMidTelescope:
telescope = std::make_unique<telescope::SkaMid>(ms, options);
break;
+ case kVLATelescope: {
+ auto coefs = std::make_unique<circularsymmetric::VLACoefficients>("");
+ telescope =
+ std::make_unique<telescope::Dish>(ms, std::move(coefs), options);
+ } break;
default:
casacore::ScalarColumn<casacore::String> telescope_name_col(
ms.observation(), "TELESCOPE_NAME");
diff --git a/cpp/load.h b/cpp/load.h
index 35294e82..6f87dca4 100644
--- a/cpp/load.h
+++ b/cpp/load.h
@@ -21,6 +21,7 @@ enum TelescopeType {
kATCATelescope,
kGMRTTelescope,
kLofarTelescope,
+ kMeerKATTelescope,
kOSKARTelescope,
kMWATelescope,
kSkaMidTelescope,
--
GitLab