chetnaduggal / ifu-3D-datacube-analysis

Analysis of the SINFONI integral-field data for powerful radio-quasar 3C 297

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Integral-field (3D) datacube analysis for a quasar-host merger system

movie

The codes and results in this repository are part of an ongoing study of the host galaxy of quasar 3C 297. The observations were obtained (Cycle 97 program 097.B-0452A; PI G. Tremblay) from the now-decomissioned SINFONI instrument at the ESO Very Large Telescope (VLT), Chile. The data are now in public domain and the raw files are available here.


Data

The H-band (1.45−1.85 μm) data were reduced using the standard ESO-SINFONI pipeline. After sky subtraction and wavelength calibration, the final co-added data cube has a spatial scale of 0.125′′ per pix. The field of view is 8′′ × 8′′. The angular resolution is ∼0.4′′ as sampled by the point-spread function (PSF) from the standard star observations. At the target redshift, this translates to spatial resolution of ∼3 kpc.

The galaxy has a highly perturbed morphology, with a prominent arc towards north of the core. A quick look at the line profiles over the field of view (FOV) showed that the broad line emission is limited to the nuclear region-- which also shows blue-to-red shift roughly around the twin AGN (blue '+' marks). The northern arc-like feature only shows narrow line emission and bright UV emission in the HST-SINFONI overlay.

Thus, some of the analyses are divided spatially into the "nuclear" and "northern arc" regions.

Codes

  • pipelined_FOV_fitting_&_maps | The main code-- automated spaxel-wise spectral modelling over a 30x34 mini-cube centered on the core. The line flux, velocity and velocity dispersion information is also recorded for each spaxel for 2D map construction.

The .py file shows the code at a glance, while the .ipynb file with the fitting outputs for 1020 spaxels is too large for Github to display.

  • 3c297_broad&narrow_line_maps.ipynb | Creating line flux, velocity and velocity dispersion maps for all the detected lines in 3c297 spectrum (Halpha, [N II] and [S II]).
  • spaxelwise_Nuclear7x7_NorthernArc.ipynb | This script does spaxel-wise line fitting on the nuclear 7x7 spaxel region and the northern arc. Each output shows the resulting fit values and plots the model+residuals on the observed spectrum.
  • 3c297_overlays.ipynb | Multi-band overlays for comparing emission in the optical, UV, radio and line-emitting gas.
  • WHAN_diagnostic_spaxelwise.ipynb | Script to perform WHAN emission-line diagnostics to find out the source of ionization of the narrow-line emitting gas.
  • telluricOH_fitting.ipynb | Computing instrumental line broadening from telluric OH lines in the pre-background subtraction datacube.
  • generate_error_cube.ipynb | This script creates an "error cube" form the noise in the observed data, for fittting uncertainty computations.
  • 3x3central_leastsq_coupledfit.ipynb | A simple script that illustrates the 6-component Gaussian fitting used for spectral modelling in our analysis. Integrating the spectra of the central 3x3 spaxel region, the modelling shows a clear broad component in Halpha.

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Analysis of the SINFONI integral-field data for powerful radio-quasar 3C 297

License:MIT License


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