ﻻ يوجد ملخص باللغة العربية
We observed with ALMA three deeply buried nuclei in two galaxies, NGC 4418 and Arp 220, at $sim$0.2$$ resolution over a total bandwidth of 67 GHz in $f_{rm rest}$ = 215 - 697 GHz. Here we (1) introduce our program, (2) describe our data reduction method for wide-band, high-resolution imaging spectroscopy, (3) analyze in visibilities the compact nuclei with line forests, (4) develop a continuum-based estimation method of dust opacity and gas column density in heavily obscured nuclei, which uses the BGN (buried galactic nuclei) model and is sensitive to $log(N_{rm H_2}/{rm cm}^{-2}) sim $ 25 - 26 at $lambda sim 1$ mm, and (5) present the continuum data and diagnosis of our targets. The three continuum nuclei have major-axis FWHM of $sim$0.1$$-0.3$$ (20-140 pc) aligned to their rotating nuclear disks of molecular gas. However, each nucleus is described better with two or three concentric components than with a single Gaussian. The innermost cores have sizes of 0.05$$-0.10$$ (8-40 pc), peak brightness temperatures of ~100-500 K at 350 GHz, and more fractional flux at lower frequencies. The intermediate components correspond to the nuclear disks. They have axial ratios of $approx$0.5 and hence inclinations $stackrel{>}{sim} 60$ deg. The outermost elements include the bipolar outflow from Arp 220W. We estimate 1 mm dust opacity of $tau_{rm d,1mm} approx 2.2$, $1.2$, and $stackrel{<}{sim} 0.4$ respectively for NGC 4418, Arp 220W, and Arp 220E. The first two correspond to $log(N_{rm H}/{rm cm}^{-2}) sim 26$ for conventional dust-opacity laws, and hence the nuclei are highly Compton thick.
We analyze 3 mm emission of the ultraluminous infrared galaxy Arp 220 for spatially-resolved structure and spectral properties of the merger nuclei. ALMA archival data at ~0.05 resolution are used for extensive visibility fitting and deep imaging of
We report the results of HCN(J=4-3) and HCO+(J=4-3) observations of two luminous infrared galaxies (LIRGs), NGC 4418 and Arp 220, made using the Atacama Submillimeter Telescope Experiment (ASTE). The ASTE wide-band correlator provided simultaneous ob
We obtained an ALMA Cycle 0 spectral scan of the dusty LIRG NGC 4418, spanning a total of 70.7 GHz in bands 3, 6, and 7. We use a combined local thermal equilibrium (LTE) and non-LTE (NLTE) fit of the spectrum in order to identify the molecular speci
We report ALMA Band 7 (350 GHz) imaging at 0.4 - 0.6arcsec resolution and Band 9 (696 GHz) at ~0.25arcsec resolution of the luminous IR galaxies Arp 220 and NGC 6240. The long wavelength dust continuum is used to estimate ISM masses for Arp 220 East,
In external galaxies, molecular composition may be influenced by extreme environments such as starbursts and galaxy mergers. To study such molecular chemistry, we observed the luminous-infrared galaxy and merger NGC 3256 using the Atacama Large Milli