اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدDetection of an ultra-bright submillimeter galaxy behind the Small Magellanic Cloud
93
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We report the discovery of a new ultra-bright submillimeter galaxy (SMG) behind the Small Magellanic Cloud (SMC). This SMG is detected as a 43.3+-8.4 mJy point source (MM J01071-7302, hereafter MMJ0107) in the 1.1 mm continuum survey of the SMC by AzTEC on the ASTE telescope. MMJ0107 is also detected in the radio (843 MHz), Herschel/SPIRE, Spitzer MIPS 24 {mu}m, all IRAC bands, Wide-field Infrared Survey Explorer, and near-infrared (J, H, KS). We find an optical (U, B, V) source, which might be the lensing object, at a distance of 1.4 arcsec from near-infrared and IRAC sources. Photometric redshift estimates for the SMG using representative spectral energy distribution templates show the redshifts of 1.4-3.9. We estimate total far-infrared luminosity of (0.3-2.2)x10^14 {mu}^-1 L_sun and a star formation rate of 5600-39, 000 {mu}^-1 M_sun yr^-1, where {mu} is the gravitational magnification factor. This apparent extreme star formation activity is likely explained by a highly magnified gravitational lens system.
قيم البحث
اقرأ أيضاً
We report the detection of an extremely bright ($sim$37 mJy at 1100 $mu$m and $sim$91 mJy at 880 $mu$m) submillimeter galaxy (SMG), AzTEC-ASTE-SXDF1100.001 (hereafter referred to as SXDF1100.001 or Orochi), discovered in 1100 $mu$m observations of th
e Subaru/XMM-Newton Deep Field using AzTEC on ASTE. Subsequent CARMA 1300 $mu$m and SMA 880 $mu$m observations successfully pinpoint the location of Orochi and suggest that it has two components, one extended (FWHM of $sim$ 4$^{primeprime}$) and one compact (unresolved). Z-Spec on CSO has also been used to obtain a wide band spectrum from 190 to 308 GHz, although no significant emission/absorption lines are found. The derived upper limit to the line-to-continuum flux ratio is 0.1--0.3 (2 $sigma$) across the Z-Spec band. Based on the analysis of the derived spectral energy distribution from optical to radio wavelengths of possible counterparts near the SMA/CARMA peak position, we suggest that Orochi is a lensed, optically dark SMG lying at $z sim 3.4$ behind a foreground, optically visible (but red) galaxy at $z sim 1.4$. The deduced apparent (i.e., no correction for magnification) infrared luminosity ($L_{rm IR}$) and star formation rate (SFR) are $6 times 10^{13}$ $L_{odot}$ and 11000 $M_{odot}$ yr$^{-1}$, respectively, assuming that the $L_{rm IR}$ is dominated by star formation. These values suggest that Orochi will consume its gas reservoir within a short time scale ($3 times 10^{7}$ yr), which is indeed comparable to those in extreme starbursts like the centres of local ULIRGs.
We report the spectroscopic confirmation of 29 new, 12 plausible, and 3 previously known quasars behind the central ~1.5 deg^2 region of the Small Magellanic Cloud. These were identified in a single 2df/AAOmega observation on the Anglo-Australian Tel
escope of 268 candidates selected primarily based on their mid-IR colors, along with a smaller number of optically variable sources in OGLE-II close to known X-ray sources. The low detection efficiency was partly expected from the high surface density of SMC as compared to the LMC targets and the faintness of many of them (149 with I>20 mag). The expected number of I<20 mag quasars in the field is ~38, and we found 15 (22 with plausible) or 40% (60%). We did not attempt to determine the nature of the remaining sources, although several appear to be new planetary nebulae. The newly discovered AGNs can be used as reference points for future proper motion studies, to study absorption in the interstellar medium, and to study the physics of quasar variability with the existing long-term, highly cadenced OGLE light curves.
We present followup spectroscopic observations of quasar candidates in the Small Magellanic Cloud selected by Eyer from the OGLE database. Of twelve observed objects identified as QSO Candidate, five are confirmed quasars, with the emission redshifts
ranging from 0.28 to 2.16. Two of those quasars were also recently identified independently in the MACHO database by Geha et al. We discuss the prospects of using variability-based selection technique for quasar searches behind other dense stellar fields. An additional criterion utilizing the color-color diagram should reduce the number of stars in the candidate lists.
We present five X-ray quasars behind the Small Magellanic Cloud, increasing the number of known quasars behind the SMC by ca. 40%. They were identified via follow-up spectroscopy of serendipitous sources from the Chandra X-ray Observatory matched wit
h objects from the OGLE database. All quasars lie behind dense parts of the SMC, and could be very useful for proper motion studies. We analyze X-ray spectral and timing properties of the quasars. We discuss applications of those and other recently discovered quasars behind the SMC to the studies of absorption properties of the Cloud, its proper motion, and for establishing the geometrical distance to the SMC.
Serendipitously we have discovered a rare, bright submillimeter galaxy (SMG) with a flux density of 30 +/- 2 mJy at lambda=1.2mm, using MAMBO2 at the IRAM 30-meter millimeter telescope. Although no optical counterpart is known for MM18423+5938, we we
re able to measure the redshift z=3.92960 +/- 0.00013 from the detection of CO lines using the IRAM Eight MIxer Receiver (EMIR). In addition, by collecting all available photometric data in the far-infrared and radio to constrain its spectral energy distribution, we derive the FIR luminosity 4.8 10^14/m Lsol and mass 6.0 10^9/m Msol for its dust, allowing for a magnification factor m caused by a probable gravitational lens. The corresponding star-formation rate is 8.3 10^4/m Msol/yr. The detection of three lines of the CO rotational ladder, and a significant upper limit for a fourth CO line, allow us to estimate an H2 mass of between 1.9 10^11/m Msol and 1.1 10^12/m Msol. The two lines CI(3p1-3p0) and CI(3p2-3p1) were clearly detected and yield a [CI]/[H2] number abundance between 1.4 10^-5 and 8.0 10^-5. Upper limits are presented for emission lines of HCN, HCO^+, HNC, H_2O and other molecules observed. The moderate excitation of the CO lines is indicative of an extended starburst, and excludes the dominance of an AGN in heating this high-redshift SMG.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
