We present the full data release of the 12CO (3–2) High-Resolution Survey (COHRS), which has mapped the inner Galactic plane over the range of 9.°5 ≤ l ≤ 62.°3 and ∣b∣ ≤ 0.°5. COHRS has been carried ...out using the Heterodyne Array Receiver Program on the 15 m James Clerk Maxwell Telescope in Hawaii. The released data are smoothed to have a spatial resolution of 16.″6 and a velocity resolution of 0.635 km s−1, achieving a mean rms of ∼0.6 K on TA*. The COHRS data are useful for investigating detailed three-dimensional structures of individual molecular clouds and large-scale structures such as spiral arms in the Galactic plane. Furthermore, data from other available public surveys of different CO isotopologues and transitions with similar angular resolutions to this survey, such as FUGIN, SEDIGISM, and CHIMPS/CHIMPS2, allow studies of the physical properties of molecular clouds and comparison of their states. In this paper, we report further observations on the second release and improved data reduction since the original COHRS release. We discuss the characteristics of the COHRS data and present integrated-emission images and a position–velocity (PV) map of the region covered. The PV map shows a good match with spiral-arm traces from existing CO and H i surveys. We also obtain and compare integrated one-dimensional distributions of 12CO (1–0) and (3–2) and those of star-forming populations.
Abstract
The Submillimetre Common User Bolometer Array 2 (SCUBA-2) is the James Clerk Maxwell Telescope’s continuum imager, operating simultaneously at 450 and 850
μ
m. SCUBA-2 was commissioned in ...2009–2011, and since that time, regular observations of point-like standard sources have been performed whenever the instrument is in use. Expanding the calibrator observation sample by an order of magnitude compared to previous work, in this paper we derive updated opacity relations at each wavelength for a new atmospheric extinction correction, analyze the Flux Conversion Factors used to convert instrumental units to physical flux units as a function of date and observation time, present information on the beam profiles for each wavelength, and update secondary calibrator source fluxes. Between 07:00 and 17:00 UTC, the portion of the night that is most stable to temperature gradients that cause dish deformation, the total flux uncertainty and the peak flux uncertainty measured at 450
μ
m are found to be 14% and 17%, respectively. Measured at 850
μ
m, the total flux and peak flux uncertainties are 6% and 7%, respectively. The analysis presented in this work is applicable to all SCUBA-2 projects observed since 2011.
Abstract
We present the first detection of pulsations from a neutron star in the submillimeter range. The source is the magnetar XTE J1810−197, observed with the James Clerk Maxwell Telescope on 2020 ...February 27, 2020 July 9, and 2021 May 15. XTE J1810−197 is detected at 353 GHz (
λ
= 0.85 mm) in the three epochs, but not detected in the simultaneously observed band at 666 GHz (
λ
= 0.45 mm). We measure an averaged flux density at 353 GHz of 6.7 ± 1.0, 4.0 ± 0.6, and 1.3 ± 0.3 mJy, and set 3
σ
flux density upper limits at 666 GHz of 11.3, 4.7, and 4.3 mJy, at each of the three observing epochs, respectively. Combining close-in-time observations with the Effelsberg 100 m and IRAM 30 m telescopes covering noncontiguously from 6 to 225 GHz (5.0 cm >
λ
> 1.33 mm), we investigate the spectral shape and frequency range of a potential spectral turn-up predicted by some pulsar radio emission models. The results demonstrate that the beamed radio emission from neutron stars can extend into the submillimeter regime, but are inconclusive on the existence and location of a potential spectral turn-up within the covered frequency range. The observed properties of the submillimeter emission resemble those of longer wavelengths and support a coherent mechanism for the production of pulsations at 353 GHz.
Abstract
We present the full data release of the
12
CO (3–2) High-Resolution Survey (COHRS), which has mapped the inner Galactic plane over the range of 9.°5 ≤
l
≤ 62.°3 and ∣
b
∣ ≤ 0.°5. COHRS has ...been carried out using the Heterodyne Array Receiver Program on the 15 m James Clerk Maxwell Telescope in Hawaii. The released data are smoothed to have a spatial resolution of 16.″6 and a velocity resolution of 0.635 km s
−1
, achieving a mean rms of ∼0.6 K on
T
A
*
. The COHRS data are useful for investigating detailed three-dimensional structures of individual molecular clouds and large-scale structures such as spiral arms in the Galactic plane. Furthermore, data from other available public surveys of different CO isotopologues and transitions with similar angular resolutions to this survey, such as FUGIN, SEDIGISM, and CHIMPS/CHIMPS2, allow studies of the physical properties of molecular clouds and comparison of their states. In this paper, we report further observations on the second release and improved data reduction since the original COHRS release. We discuss the characteristics of the COHRS data and present integrated-emission images and a position–velocity (PV) map of the region covered. The PV map shows a good match with spiral-arm traces from existing CO and H
i
surveys. We also obtain and compare integrated one-dimensional distributions of
12
CO (1–0) and (3–2) and those of star-forming populations.
We present the full data release of 12CO (3-2) High-Resolution Survey (COHRS), which has mapped the inner Galactic plane over the range of 9.5\(^{\circ}\) \(\le\) l \(\le\) 62.3\(^{\circ}\) and \(|b| ...\le 0.5^{\circ}\). The COHRS has been carried out using the Heterodyne Array Receiver Program (HARP) on the 15 m James Clerk Maxwell Telescope (JCMT) in Hawaii. The released data are smoothed to have a spatial resolution of 16.6 arcsec and a velocity resolution of 0.635 km/s, achieving a mean root-mean-square of \(\sim 0.6\) K on \(T_\mathrm{A}^*\). The COHRS data are useful for investigating detailed three-dimensional structures of individual molecular clouds and large-scale structures such as spiral arms in the Galactic plane. Furthermore, data from other available public surveys of different CO isotopologues and transitions with similar angular resolutions to this survey, such as FUGIN, SEDIGISM, and CHIMPS/CHIMPS2, allow studying the physical properties of molecular clouds and comparing their states with each other. In this paper, we report further observations on R2 and improved data reduction since the original COHRS release. We discuss the characteristics of the COHRS data and present integrated-emission images and a position-velocity (PV) map of the region covered. The PV map shows a good match with the spiral-arm traces from the existing CO and HI surveys. We also obtain and compare integrated one-dimensional distributions of 12CO (1-0) and (3-2) and those of star-forming populations to each other.
We present the first detection of pulsations from a neutron star in the submillimeter range. The source is the magnetar XTE J1810-197, observed with the James Clerk Maxwell Telescope (JCMT) on 2020 ...February 27, 2020 July 9 and 2021 May 15. XTE J1810-197 is detected at 353 GHz (\(\lambda=0.85\,\)mm) in the three epochs, but not detected in the simultaneously-observed band at 666 GHz (\(\lambda=0.45\,\)mm). We measure an averaged flux density at 353 GHz of 6.7\(\pm\)1.0, 4.0\(\pm\)0.6, and 1.3\(\pm\)0.3 mJy and set 3\(\sigma\) flux density upper limits at 666 GHz of 11.3, 4.7 and 4.3 mJy, at each of the three observing epochs, respectively. Combining close-in-time observations with the Effelsberg 100m and IRAM 30m telescopes covering non-contiguously from 6 to 225 GHz (5.0 cm\(>\lambda>\)1.33 mm), we investigate the spectral shape and frequency range of a potential spectral turn-up predicted by some pulsar radio emission models. The results demonstrate that the beamed radio emission from neutron stars can extend into the submillimeter regime, but are inconclusive on the existence and location of a potential spectral turn-up within the covered frequency range. The observed properties of the submillimeter emission resemble those of the longer wavelengths, and support a coherent mechanism for the production of pulsations at 353 GHz.
The Submillimetre Common User Bolometer Array 2 (SCUBA-2) is the James Clerk
Maxwell Telescope's continuum imager, operating simultaneously at 450 and
850~$\mu$m. SCUBA-2 was commissioned in ...2009--2011 and since that time, regular
observations of point-like standard sources have been performed whenever the
instrument is in use. Expanding the calibrator observation sample by an order
of magnitude compared to previous work, in this paper we derive updated opacity
relations at each wavelength for a new atmospheric-extinction correction,
analyze the Flux-Conversion Factors (FCFs) used to convert instrumental units
to physical flux units as a function of date and observation time, present
information on the beam profiles for each wavelength, and update
secondary-calibrator source fluxes. Between 07:00 and 17:00 UTC, the portion of
the night that is most stable to temperature gradients that cause dish
deformation, the total-flux uncertainty and the peak-flux uncertainty measured
at 450~$\mu$m are found to be 14\% and 17\%, respectively. Measured at
850~$\mu$m, the total-flux and peak-flux uncertainties are 6\%, and 7\%,
respectively. The analysis presented in this work is applicable to all SCUBA-2
projects observed since 2011.
SCUBA-2 is a 10,000 pixel wide field sub-millimeter camera which started science observing on James Clerk Maxwell Telescope (JCMT) in the spring of 2010. We present the results of characterising ...individual 1280 bolometer science grade sub-arrays, as well as experience from operating the instrument.
PDF
