Observations of NGC1068 with DESHIMA 2.0
Verifying the science capabilities of the inte- grated superconducting spectrometer
M.J. Endtz (TU Delft - Applied Sciences)
A Endo β Mentor (TU Delft - Tera-Hertz Sensing)
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Abstract
The single-pixel integrated superconducting spectrometer DESHIMA 2.0 on 10 m Atacama Submillimeter Telescope Experiment (ASTE) aims to provide broadband spectra from 200 to 400 GHz at medium resolution. This spectral range enables observations of (sub) millimetre-wave astronomy, especially for uncovering dust-obscured cosmic star formation and galaxy evolution over cosmic time. To test its scientific capabilities, the nearby star-forming and AGN galaxy NGC 1068 was observed. This study compares the observed DESHIMA 2.0 spectrum against published literature on NGC 1068, addressing the research question: Is the wideband spectrum of NGC 1068 obtained with DESHIMA 2.0 consistent with pre- viously published observational data?
The dust continuum was extracted by fitting a grey-body with a statistical model using a Markov Chain Monte Carlo (MCMC) sampler over the 250-280 GHz window. The best-fit parameters were found to agree with values obtained by Z-spec at the 1π level, with a reduced π2 = 1.37 achieved with the data and π2 = 3.32 with continuum model over Z-spec observed data, showing good continuum recovery. Voigt profiles were fitted to the CO(2-1) and CO(3-2) lines using single fits on continuum-subtracted spectra. The emission line fluxes comparable to those obtained with the James Clerk Maxwell Telescope (JCMT) by Qiu et al. were measured by DESHIMA 2.0, agreeing within 6β12%. However, significant differences were observed in line widths and main beam temperatures, attributed to instrumental effects such as beam dilution and smearing, as well as methodological differences between single Voigt profile and multi-component Gaussian fitting approaches.
It is demonstrated that DESHIMA 2.0 delivers reliable broadband continuum and integrated emission line fluxes consistent with other instruments for NGC 1068, validating its utility for spectral surveys of bright dusty star-forming galaxies. The observed differences in line widths and channel-to-channel calibration highlight opportunities for improved MKID correspondence and noise reduction to enable the detection of fainter emission lines in future observations.