The CO spectra of dust-rich broad-emission-line quasars

During 2011-2013, we used the IRAM-30m telescope to observe the CO emission lines of selected samples. The E090, E150, and E230 wavebands of the Eight Mixer Receiver (EMIR) front-end receiver were used for observation, covering atmospheric windows of 3, 2, and 1.3 millimeters, respectively, with corresponding beam sizes (HPBW) of about 29, 16, and 11 angular seconds. EMIR consists of two sidebands, each 7.44 GHz wide, called LSB and USB, each divided into two equally wide basebands. Under the redshifts of the target sources, the speed coverage range corresponding to a single baseband is approximately 5000–10000 km/s. The back-end used for observation is a broadband autocorrelator called WILMA, which consists of 16 units, each covering 512 channels with a spectral resolution of 2 MHz, and the corresponding original velocity resolution is about 3−6 km/s. The obtained single baseband spectral data are processed using the CLASS software in GILDAS. According to the standard process of IRAM-30m data processing, we first use a window of about 100 km/s to cover the spike noise in a single exposure, replace the signal within the window with random Gaussian noise obtained by first-order polynomial baseline fitting, and remove the platform effect. Subsequently, we integrate multiple exposures. The integrated spectrum is first smoothed to a spectral resolution of about 60 km/s, and then baseline deductions are made for the entire baseband except for the spectral line position. For narrow spectral lines found after measurement (such as the CO (5-4) line of LHS-S072, FWHM ~90 km/s), the spectral resolution used is ~30 km/s. We then export the corresponding fits format data file.