We present the spectra of 14 quasars with a wide coverage of rest wavelengths from 1000 to 7300 8. The redshift ranges from z ¼ 0:061 to 0.555 and the luminosity from M B ¼ À22:69 to À26.32. These spectra of high quality result from combining Hubble Space Telescope spectra with those taken from ground-based telescopes. We describe the procedure of generating the template spectrum of Fe ii line emission from the spectrum of a narrow-line Seyfert 1 galaxy, I Zw 1, that covers two wavelength regions of 2200-3500 and 4200-5600 8. Our template Fe ii spectrum is semiempirical in the sense that the synthetic spectrum calculated with the CLOUDY photoionization code is used to separate the Fe ii emission from the Mg ii k2798 line. The procedure of measuring the strengths of Fe ii emission lines is twofold: (1) subtracting the continuum components by fitting models of the power-law and Balmer continua in the continuum windows, which are relatively free from line emissions, and (2) fitting models of the Fe ii emission based on the Fe ii template to the continuum-subtracted spectra. From 14 quasars including I Zw 1, we obtained the Fe ii fluxes in five wavelength bands (U 1 [2200-2660 8], U 2 [2660-3000 8], U 3 [3000-3500 8], O1 [4400-4700 8], and O2 [5100-5600 8]), the total flux of Balmer continuum, and the fluxes of Mg ii k2798, H, and other emission lines, together with the full widths at half-maximum (FWHMs) of these lines. Regression analysis was performed by assuming a linear relation between any two of these quantities. Eight correlations were found with a confidence level higher than 99%: (1) larger Mg ii FWHM for larger H FWHM, (2) larger À for fainter M B , (3) smaller Mg ii FWHM for larger À, (4) larger Mg ii FWHM for smaller Fe ii(O1)/ Mg ii, (5) larger M BH for smaller À, (6) larger M BH for smaller Fe ii(O1)/ Mg ii, (7) larger [O iii]/H for larger Mg ii FWHM, and (8) larger Fe ii(O1)/ Mg ii for larger Fe ii(O1)/ Fe ii(U 1).The fact that six of these eight are related to FWHM or M BH (/ FWHM 2 ) may imply that M BH is a fundamental quantity that controls À or the spectral energy distribution (SED) of the incident continuum, which in turn controls the Fe ii emission. Furthermore, it is worthy of noting that Fe ii(O1)/ Fe ii(U 1) is found to tightly correlate with Fe ii(O1)/ Mg ii, but not with Fe ii(U 1)/ Mg ii.
We present the results of an unbiased asteroid survey in the mid-infrared wavelength region with the Infrared Camera (IRC) on board the Japanese infrared satellite AKARI. About 20% of the point source events recorded in the AKARI All-Sky Survey observations are not used for the IRC Point Source Catalog (IRC-PSC) in its production process because of a lack of multiple detection by position. Asteroids, which are moving objects on the celestial sphere, remain in these "residual events". We identify asteroids out of the residual events by matching them with the positions of known asteroids. For the identified asteroids, we calculate the size and albedo based on the Standard Thermal Model. Finally we have a new brand of asteroid catalog, named the Asteroid Catalog Using AKARI (AcuA), which contains 5120 objects, about twice as many as the IRAS asteroid catalog. The catalog objects comprise 4953 main belt asteroids, 58 near-Earth asteroids, and 109 Jovian Trojan asteroids. The catalog is publicly available via the Internet.
Context. AKARI is the first Japanese astronomical satellite dedicated to infrared astronomy. One of the main purposes of AKARI is the all-sky survey performed with six infrared bands between 9 μm and 200 μm during the period from 2006 May 6 to 2007 August 28. In this paper, we present the mid-infrared part (9 μm and 18 μm bands) of the survey carried out with one of the on-board instruments, the infrared camera (IRC). Aims. We present unprecedented observational results of the 9 μm and 18 μm AKARI all-sky survey and detail the operation and data processing leading to the point source detection and measurements. Methods. The raw data are processed to produce small images for every scan, and the point sources candidates are derived above the 5σ noise level per single scan. The celestial coordinates and fluxes of the events are determined statistically and the reliability of their detections is secured through multiple detections of the same source within milli-seconds, hours, and months from each other. Results. The sky coverage is more than 90% for both bands. A total of 877 091 sources (851 189 for 9 μm, 195 893 for 18 μm) are confirmed and included in the current release of the point source catalog. The detection limit for point sources is 50 mJy and 90 mJy for the 9 μm and 18 μm bands, respectively. The position accuracy is estimated to be better than 2 . Uncertainties in the in-flight absolute flux calibration are estimated to be 3% for the 9 μm band and 4% for the 18 μm band. The coordinates and fluxes of detected sources in this survey are also compared with those of the IRAS survey and are found to be statistically consistent.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.