1,271 research outputs found

    A search for near infrared counterparts of 3 pulsar wind nebulae

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    While pulsar wind nebulae (PWNe) and their associated isolated pulsars are commonly detected at X-ray energies, they are much rarer at near infrared (nIR) and optical wavelengths. Here we examine three PWN systems in the Galactic plane - IGR J14003-6326, HESS J1632-478 and IGR J18490-0000 - in a bid to identify optical/nIR emission associated with either the extended PWNe or their previously detected X-ray point sources. We obtain optical/nIR images of the three fields with the ESO - New Technology Telescope and apply standard photometric and astrometric calibrations. We find no evidence of any extended emission associated with the PWNe in any of the fields; neither do we find any new counterparts to the X-ray point sources, except to confirm the magnitude of the previously identified counterpart candidate of IGR J18490-0000. Further observations are required to confirm the association of the nIR source to IGR J18490-0000 and to detect counterparts to IGR J14003-6326 and HESS J1632-478, while a more accurate X-ray position is required to reduce the probability of a chance superposition in the field of the latter.Comment: Accepted to A&A (4 pages, 1 figure

    A Review Of Implementing Adc In Rfid Sensor

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The general considerations to design a sensor interface for passive RFID tags are discussed. This way, power and timing constraints imposed by ISO/IEC 15693 and ISO/IEC 14443 standards to HF RFID tags are explored. A generic multisensor interface is proposed and a survey analysis on the most suitable analog-to-digital converters for passive RFID sensing applications is reported. The most appropriate converter type and architecture are suggested. At the end, a specific sensor interface for carbon nanotube gas sensors is proposed and a brief discussion about its implemented circuits and preliminary results is made.Region Rhone-Alpes (France)CNPq (Brazil)INCT/NAMITEC (Brazil)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    The nature of the X-ray binary IGR J19294+1816 from INTEGRAL, RXTE, and Swift observations

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    We report the results of a high-energy multi-instrumental campaign with INTEGRAL, RXTE, and Swift of the recently discovered INTEGRAL source IGR J19294+1816. The Swift/XRT data allow us to refine the position of the source to RA= 19h 29m 55.9s Dec=+18deg 18' 38.4" (+- 3.5"), which in turn permits us to identify a candidate infrared counterpart. The Swift and RXTE spectra are well fitted with absorbed power laws with hard (Gamma ~ 1) photon indices. During the longest Swift observation, we obtained evidence of absorption in true excess to the Galactic value, which may indicate some intrinsic absorption in this source. We detected a strong (P=40%) pulsation at 12.43781 (+-0.00003) s that we interpret as the spin period of a pulsar. All these results, coupled with the possible 117 day orbital period, point to IGR J19294+1816 being an HMXB with a Be companion star. However, while the long-term INTEGRAL/IBIS/ISGRI 18--40 keV light curve shows that the source spends most of its time in an undetectable state, we detect occurrences of short (~2000-3000 s) and intense flares that are more typical of supergiant fast X-ray transients. We therefore cannot make firm conclusions on the type of system, and we discuss the possible implications of IGR J19294+1816 being an SFXT.Comment: 7 pages, 6 figures, accepted for publication in A&

    A Review Of Implementing Adc In Rfid Sensor

    Get PDF
    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The general considerations to design a sensor interface for passive RFID tags are discussed. This way, power and timing constraints imposed by ISO/IEC 15693 and ISO/IEC 14443 standards to HF RFID tags are explored. A generic multisensor interface is proposed and a survey analysis on the most suitable analog-to-digital converters for passive RFID sensing applications is reported. The most appropriate converter type and architecture are suggested. At the end, a specific sensor interface for carbon nanotube gas sensors is proposed and a brief discussion about its implemented circuits and preliminary results is made.Region Rhone-Alpes (France)CNPq (Brazil)INCT/NAMITEC (Brazil)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    INTEGRAL, XMM-Newton and ESO/NTT identification of AX J1749.1-2733: an obscured and probably distant Be/X-ray binary

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    AX J1749.1-2733 is an unclassified transient X-ray source discovered during surveys by ASCA in 1993-1999. A multi-wavelength study in NIR, optical, X-rays and hard X-rays is undertaken in order to determine its nature. AX J1749.1-2733 is a new high-mass X-ray binary pulsar with an orbital period of 185.5+/-1.1 d (or 185.5/f with f=2,3 or 4) and a spin period of ~66 s, parameters typical of a Be/X-ray binary. The outbursts last ~12 d. A spin-down of 0.08+/-0.02 s/yr is also observed, very likely due to the propeller effect. The most accurate X-ray position is R.A. (2000) =17h49m06.8s and Dec. = -27deg32'32".5 (unc. 2"). The high-energy broad-band spectrum is well-fitted with an absorbed powerlaw and a high-energy cutoff with values NH=(20+/-1)e22 cm-2, Gamma=1.0+/-0.1, and Ecut=21+/-3 keV. The only optical/NIR candidate counterpart within the X-ray error circle has magnitudes of R=21.9+/-0.1, I=20.92+/-0.09, J=17.42+/-0.03, H=16.71+/-0.02, and Ks=15.75+/-0.07, which points towards a Be star located far away (> 8.5 kpc) and highly absorbed (NH~1.7e22 cm-2). The average 22-50 keV luminosity is (0.4-0.9)e36 erg/s during the long outbursts and 3e36 erg/s during the bright flare that occurred on MJD 52891 for an assumed distance of 8.5 kpc.Comment: accepted A&A, 11 pages, 9 figure

    Collider Bounds on Lee-Wick Higgs Bosons

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    We study the constraints on the Lee-Wick Higgs sector arising from direct collider searches. We work in an effective-field theory framework, where all of the Lee-Wick partners are integrated out, with the sole exception of the Lee-Wick Higgs bosons. The resulting theory is a two-Higgs doublet model where the second doublet has wrong-sign kinetic and mass terms. We include the bounds coming from direct Higgs searches at both LEP and Tevatron using the code HiggsBounds, and show the currently excluded parameter space. We also analyze the prospects of LHC Run-I, finding that with a total integrated luminosity of 5 fb 1^{-1} and a center-of-mass energy of 7 TeV, most of the parameter space for the SM-like CP-even Higgs will be probed.Comment: 26 pages, 5 figures, matches version published by PR
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