A photometric search for active Main Belt asteroids

Cikota, Stefan; Ortiz, J. L.; Cikota, Aleksandar; Morales, N.; Tancredi, G.

doi:10.1051/0004-6361/201321679

Cited by 16 publications

(16 citation statements)

References 33 publications

(49 reference statements)

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“…• 4 in P.A.. These values are consistent with both the trending analysis carried out by the FORS2 quality control team and with the independent analysis of Cikota et al (2016), based upon six years of FORS2 observations of polarimetry standard stars. At the same time, from the observations of the unpolarised standard stars we found that there is no evidence of significant instrumental polarisation (0.09% ± 0.06%) at the CHIP1 aim position.…”

Section: Polarisation Measurementsupporting

confidence: 86%

“…In general K linearly depends on λmax (e.g. Wilking et al 1982;Whittet et al 1992;Cikota et al 2016), while the maximum polarisation pmax is found to be a function of the reddening (Serkowski 1973, and references therein), pmax ∼ 0.09E(B − V ). Since λmax ∼ 555 nm (Serkowski et al 1975), which coincides with the pivot wavelength of the vHIGH filter (Sectn.…”

Section: The Rx J18565−3754 Polarisationmentioning

confidence: 99%

See 1 more Smart Citation

Evidence for vacuum birefringence from the first optical-polarimetry measurement of the isolated neutron star RX J1856.5−3754

Mignani

Testa

Caniulef

et al. 2016

Mon. Not. R. Astron. Soc.

152

137

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The "Magnificent Seven" (M7) are a group of radio-quiet Isolated Neutron Stars (INSs) discovered in the soft X-rays through their purely thermal surface emission. Owing to the large inferred magnetic fields (B ≈ 10 13 G), radiation from these sources is expected to be substantially polarised, independently on the mechanism actually responsible for the thermal emission. A large observed polarisation degree is, however, expected only if quantumelectrodynamics (QED) polarisation effects are present in the magnetised vacuum around the star. The detection of a strongly linearly polarised signal would therefore provide the first observational evidence of QED effects in the strong-field regime. While polarisation measurements in the soft X-rays are not feasible yet, optical polarisation measurements are within reach also for quite faint targets, like the M7 which have optical counterparts with magnitudes ≈ 26-28. Here, we report on the measurement of optical linear polarisation for the prototype, and brightest member, of the class, RX J1856.5−3754 (V ∼ 25.5), the first ever for one of the M7, obtained with the Very Large Telescope. We measured a polarisation degree P.D. = 16.43% ± 5.26% and a polarisation position angle P.A. = 145. • 39 ± 9. • 44, computed east of the North Celestial Meridian. The P.D. that we derive is large enough to support the presence of vacuum birefringence, as predicted by QED.

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Section: Polarisation Measurementsupporting

confidence: 86%

Section: The Rx J18565−3754 Polarisationmentioning

confidence: 99%

Evidence for vacuum birefringence from the first optical-polarimetry measurement of the isolated neutron star RX J1856.5−3754

Mignani

Testa

Caniulef

et al. 2016

Mon. Not. R. Astron. Soc.

152

137

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“…Our study indicates that for the two SNe Ia investigated dust is likely to be located at IS-scale distances. This is in conflict with findings from Cikota et al (2017), which support multiple scattering in a local environment for these SNe, but compatible with the non-detection of infrared thermal emission in SN 2014J (Johansson et al 2017). We have discussed how our results could be consistent with other peculiar properties displayed by some highly-reddened SNe Ia.…”

Section: Discussionmentioning

confidence: 60%

Estimating dust distances to Type Ia supernovae from colour excess time evolution

Bulla

Goobar

Amanullah

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present a new technique to infer dust locations towards reddened Type Ia supernovae and to help discriminate between an interstellar and a circumstellar origin for the observed extinction. Using Monte Carlo simulations, we show that the time-evolution of the light-curve shape and especially of the colour excess E(B − V ) places strong constraints on the distance between dust and the supernova. We apply our approach to two highly-reddened Type Ia supernovae for which dust distance estimates are available in the literature: SN 2006X and SN 2014J. For the former, we obtain a timevariable E(B − V ) and from this derive a distance of 27.5 +9.0 −4.9 or 22.1 +6.0 −3.8 pc depending on whether dust properties typical of the Large Magellanic Cloud (LMC) or the Milky Way (MW) are used. For the latter, instead, we obtain a constant E(B − V ) consistent with dust at distances larger than ∼ 50 and 38 pc for LMC− and MW−type dust, respectively. Values thus extracted are in excellent agreement with previous estimates for the two supernovae. Our findings suggest that dust responsible for the extinction towards these supernovae is likely to be located within interstellar clouds. We also discuss how other properties of reddened Type Ia supernovae -such as their peculiar extinction and polarization behaviour and the detection of variable, blue-shifted sodium features in some of these events -might be compatible with dust and gas at interstellar-scale distances.

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“…Small number statistics may have contributed to the possible discrepancy, and it is plausible we missed activity indications due to the limitations of visual inspection which were further compounded by an increased prevalence of background sources compared to shallower surveys. The use of a point spread function (PSF) comparison technique (e.g., Hsieh et al (2015a) or a photometric search (e.g., Cikota et al (2014)) could help us identify candidates, features we plan to investigate in future work.…”

Section: Occurrence Ratesmentioning

confidence: 99%

SAFARI: Searching Asteroids for Activity Revealing Indicators

Chandler

Curtis

Mommert

et al. 2018

PASP

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Active asteroids behave dynamically like asteroids but display comet-like comae. These objects are poorly understood, with only about 30 identified to date. We have conducted one of the deepest systematic searches for asteroid activity by making use of deep images from the Dark Energy Camera (DECam) ideally suited to the task. We looked for activity indicators amongst 11,703 unique asteroids extracted from 35,640 images. We detected three previously-identified active asteroids ((62412), (1) Ceres and (779) Nina), though only (62412) showed signs of activity. Our activity occurrence rate of 1 in 11,703 is consistent with the prevailing 1 in 10,000 activity occurrence rate estimate. Our proof of concept demonstrates 1) our novel informatics approach can locate active asteroids and 2) DECam data are well-suited to the search for active asteroids.

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A photometric search for active Main Belt asteroids

Cited by 16 publications

References 33 publications

Evidence for vacuum birefringence from the first optical-polarimetry measurement of the isolated neutron star RX J1856.5−3754

Evidence for vacuum birefringence from the first optical-polarimetry measurement of the isolated neutron star RX J1856.5−3754

Estimating dust distances to Type Ia supernovae from colour excess time evolution

SAFARI: Searching Asteroids for Activity Revealing Indicators

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