904 research outputs found
The Far-Infrared Luminosity Function from GOODS-N: Constraining the Evolution of Infrared Galaxies for z \leq 1
We present the IR luminosity function derived from ultra-deep 70 micron
imaging of the GOODS-North field. The 70 micron observations are longward of
the PAH and silicate features which complicate work in the MIR. We derive
far-infrared luminosities for the 143 sources with S_{70} > 2 mJy (S/N > 3
\sigma). The majority (81%) of the sources have spectroscopic redshifts, and
photometric redshifts are calculated for the remainder. The IR luminosity
function at four redshifts (z ~ 0.28, 0.48, 0.78, and 0.97) is derived and
compared to the local one. There is considerable degeneracy between luminosity
and density evolution. If the evolving luminosity function is described as
\rho(L, z) = (1 + z)^q \rho(L/(1 + z)^p, 0), we find q = -2.19p + 6.09. In the
case of pure luminosity evolution, we find a best fit of p =
2.78^{+0.34}_{-0.32}. This is consistent with the results from 24 micron and
1.4 GHz studies. Our results confirm the emerging picture of strong evolution
in LIRGs and ULIRGs at 0.4 < z < 1.1, but we find no evidence of significant
evolution in the sub-LIRG (L < 10^{11} L_{\odot}) population for z < 0.4.Comment: accepted by ApJL, 5 page
CARMA observations of massive Planck-discovered cluster candidates at z>0.5 associated with WISE overdensities: Breaking the size-flux degeneracy
We use a Bayesian software package to analyze CARMA-8 data towards 19
unconfirmed Planck SZ-cluster candidates from Rodriguez-Gonzalvez et al.
(2015), that are associated with significant overdensities in WISE. We used two
cluster parameterizations, one based on a (fixed shape) generalized-NFW
pressure profile and another based on a beta-gas-density profile (with varying
shape parameters) to obtain parameter estimates for the nine CARMA-8
SZ-detected clusters. We find our sample is comprised of massive,
Y_{500}=0.0010 \pm 0.0015 arcmin^2, relatively compact, theta_{500}= 3.9 \pm
2.0 arcmin systems. Results from the beta model show that our cluster
candidates exhibit a heterogeneous set of brightness-temperature profiles.
Comparison of Planck and CARMA-8 measurements showed good agreement in Y_{500}
and an absence of obvious biases. We estimated the total cluster mass M_{500}
as a function of z for one of the systems; at the preferred photometric
redshift of 0.5, the derived mass, M_{500} \approx 0.8 \pm 0.2 \times 10^{15}
Msun. Spectroscopic Keck/MOSFIRE data confirmed a galaxy member of one of our
cluster candidates to be at z=0.565. Applying a Planck prior in Y_{500} to the
CARMA-8 results reduces uncertainties for both parameters by a factor >4,
relative to the independent Planck or CARMA-8 measurements. We here demonstrate
a powerful technique to find massive clusters at intermediate z \gtrsim 0.5
redshifts using a cross-correlation between Planck and WISE data, with
high-resolution follow-up with CARMA-8. We also use the combined capabilities
of Planck and CARMA-8 to obtain a dramatic reduction by a factor of several, in
parameter uncertainties.Comment: 26 pages, 8 figures, appearing in MNRAS (responded to referee report
Spitzer 70 Micron Source Counts in GOODS-North
We present ultradeep Spitzer 70 ÎŒm observations of GOODS-North (Great Observatories Origins Deep Survey). For the first time, the turnover in the 70 ÎŒm Euclidean-normalized differential source counts is observed. We derive source counts down to a flux density of 1.2 mJy. From the measured source counts and fluctuation analysis, we estimate a power-law approximation of the faint 70 ÎŒm source counts of dN/dS â S^â1.6, consistent with that observed for the faint 24 ÎŒm sources. An extrapolation of the 70 ÎŒm source counts to zero flux density implies a total extragalactic background light (EBL) of 7.4 ± 1.9 nW m^â2 sr^â1. The source counts above 1.2 mJy account for about 60% of the estimated EBL. From fluctuation analysis, we derive a photometric confusion level of Ïc = 0.30 ± 0.15 mJy (q = 5) for the Spitzer 70 ÎŒm band
Preconcentration and Heavy Minerals Separation with Low Grade Beach Sand Sample from Narsapur Coast, West Godavari District, Andhra Pradesh
India is blessed with large reserves of strategic and economically important heavy minerals such as Ilmenite, Rutile, Leucoxene, Zircon, Monazite, Garnet and Sillimanite.
These deposits are mostly located in the coastal stretches of peninsular India covering states of Orissa, Andhra pradesh, Tamil nadu, Kerala and Maharastra
Spitzer Observations of the z=2.73 Lensed Lyman Break Galaxy, MS1512-cB58
We present Spitzer infrared (IR) photometry and spectroscopy of the lensed
Lyman break galaxy (LBG), MS1512-cB58 at z=2.73. The large (factor ~30)
magnification allows for the most detailed infrared study of an L*_UV(z=3) LBG
to date. Broadband photometry with IRAC (3-10 micron), IRS (16 micron), and
MIPS (24, 70 & 160 micron) was obtained as well as IRS spectroscopy spanning
5.5-35 microns. A fit of stellar population models to the optical/near-IR/IRAC
photometry gives a young age (~9 Myr), forming stars at ~98 M_sun/yr, with a
total stellar mass of ~10^9 M_sun formed thus far. The existence of an old
stellar population with twice the stellar mass can not be ruled out. IR
spectral energy distribution fits to the 24 and 70 micron photometry, as well
as previously obtained submm/mm, data give an intrinsic IR luminosity L_IR =
1-2 x10^11 L_sun and a star formation rate, SFR ~20-40 M_sun/yr. The UV derived
star formation rate (SFR) is ~3-5 times higher than the SFR determined using
L_IR or L_Halpha because the red UV spectral slope is significantly over
predicting the level of dust extinction. This suggests that the assumed
Calzetti starburst obscuration law may not be valid for young LBGs. We detect
strong line emission from Polycyclic Aromatic Hydrocarbons (PAHs) at 6.2, 7.7,
and 8.6 microns. The line ratios are consistent with ratios observed in both
local and high redshift starbursts. Both the PAH and rest-frame 8 micron
luminosities predict the total L_IR based on previously measured relations in
starbursts. Finally, we do not detect the 3.3 micron PAH feature. This is
marginally inconsistent with some PAH emission models, but still consistent
with PAH ratios measured in many local star-forming galaxies.Comment: Accepted for publication in ApJ. aastex format, 18 pages, 7 figure
AN IOT BASED WEB PAGE CONTROLLED DIGITAL NOTICE BOARD
In this proposed system the idea of IOT Based Web Controlled Digital Notice Board Using GSM Technology has been presented. So our main aim is to reduce paper work and time At present, when information has to be updated in a notice board, it has to be done manually. To change message on display, it needs to change microcontroller program code again. By adding web controlled IOT based communication interface to this system, we can make smart noticeboard to overcome these limitations. So we have interfaced web controlled IOT based SIM800L modem with microcontroller and implemented a text transmission and reception technique
Refined procedures for accurate determination of solution structures of nucleic acids by two dimensional nuclear magnetic resonance spectroscopy
New procedures have been described for accurate determination of solution structures of nucleic acids. These are two fold; new two dimensional nuclear magnetic resonance techniques and better approaches for interpretation of nuclear magnetic resonance data for structure determination purposes. The significant development in two dimensional nuclear magnetic resonance techniques for this purpose are ω1 -scaling and recording of pure phase spectra. Use ofω1-scaled correlated and nuclear Overhauser effect spectra for estimation of interproton distances and 1H-1H coupling constants has been described. Computer simulation procedures for exact determination of structure have been described. Experimental spectra demonstrating the application of new procedures have been presented
Far-ultraviolet imaging of the Hubble Deep Field-North: Star formation in normal galaxies at z < 1
We present far-ultraviolet (FUV) imaging of the Hubble Deep Field-North (HDF-N) taken with the Solar Blind Channel of the Advanced Camera for Surveys (ACS SBC) and the FUV MAMA detector of the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope. The full WFPC2 deep field has been observed at 1600 Ă
. We detect 134 galaxies and one star down to a limit of FUV_(AB) ~ 29. All sources have counterparts in the WFPC2 image. Redshifts (spectroscopic or photometric) for the detected sources are in the range 0 < z < 1. We find that the FUV galaxy number counts are higher than those reported by GALEX, which we attribute at least in part to cosmic variance in the small HDF-N field of view. Six of the 13 Chandra sources at z < 0.85 in the HDF-N are detected in the FUV, and those are consistent with starbursts rather than active galactic nuclei. Cross-correlating with Spitzer sources in the field, we find that the FUV detections show general agreement with the expected L_(IR)/L_(UV) versus ÎČ relationship. We infer star formation rates (SFRs), corrected for extinction using the UV slope, and find a median value of 0.3 M_â yr^(-1) for FUV-detected galaxies, with 75% of detected sources having SFR < 1 M_â yr^(-1). Examining the morphological distribution of sources, we find that about half of all FUV-detected sources are identified as spiral galaxies. Half of morphologically selected spheroid galaxies at z < 0.85 are detected in the FUV, suggesting that such sources have had significant ongoing star formation in the epoch since z ~ 1
An Accounting of the Dust-Obscured Star Formation and Accretion Histories Over the Last ~11~Billion Years
(Abridged) We report on an accounting of the star formation and accretion
driven energetics of 24um detected sources in GOODS North. For sources having
infrared (IR; 8-1000um) luminosities >3x10^12 L_sun when derived by fitting
local SEDs to 24um photometry alone, we find these IR luminosity estimates to
be a factor of ~4 times larger than those estimated when the SED fitting
includes additional 16 and 70um data (and in some cases mid-infrared
spectroscopy and 850um data). This discrepancy arises from the fact that high
luminosity sources at z>>0 appear to have far- to mid-infrared ratios, as well
as aromatic feature equivalent widths, typical of lower luminosity galaxies in
the local Universe. Using our improved estimates for IR luminosity and AGN
contributions, we investigate the evolution of the IR luminosity density versus
redshift arising from star formation and AGN processes alone. We find that,
within the uncertainties, the total star formation driven IR luminosity density
is constant between 1.15 < z < 2.35, although our results suggest a slightly
larger value at z>2. AGN appear to account for <18% of the total IR luminosity
density integrated between 0< z < 2.35, contributing <25% at each epoch. LIRG
appear to dominate the star formation rate (SFR) density along with normal
star-forming galaxies (L_IR < 10^11 L_sun) between 0.6 < z < 1.15. Once beyond
z >2, the contribution from ultraluminous infrared galaxies ULIRGs becomes
comparable with that of LIRGs. Using our improved IR luminosity estimates, we
find existing calibrations for UV extinction corrections based on measurements
of the UV spectral slope typically overcorrect UV luminosities by a factor of
~2, on average, for our sample of 24um-selected sources; accordingly we have
derived a new UV extinction correction more appropriate for our sample.Comment: Accepted for publication in Ap
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