Direct measurement of stellar angular diameters by the VERITAS Cherenkov telescopes

Benbow, W.; Bird, R.; Brill, A.; Brose, Robert; Daniel, M. K.; Feng, Q.; Finley, J. P.; Fortson, L.; Furniss, A.; Giuri, C.; Gueta, O.; Hanna, D.; Halpern, J. P.; Hassan, Tarek; Holder, J.; Hughes, G.; Humensky, T. B.; Joyce, Aoife; Kaaret, P.; Kar, P.; Kelley-Hoskins, N.; Kertzman, M.; Kieda, D.; Krause, M.; Lang, M. J.; Lin, T. T. Y.; Maier, G.; Matthews, Nolan; Moriarty, P.; Mukherjee, R.; Nieto, D.; Rosillo, M. Nievas; O’Brien, S.; Park, N.; Petrashyk, A.; Pohl, Martin; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Richards, G.; Roache, E.; Rulten, C. B.; Sadeh, I.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Sushch, I.; Wakely, S. P.; Wells, R. M.; Wilcox, P.; Wilhelm, A.; Williams, D. A.; Williamson, T. J.

doi:10.1038/s41550-019-0741-z

Cited by 23 publications

(19 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Yet, in the optical/UV the Rayleigh-Jeans tail of the lower temperature short burst component may be detectable as sub-second transients to greater distances with large-sized imaging atmospheric Cherenkov telescopes (or other large optical facilities) in a fast photometry mode (e.g. Deil et al 2009;Lacki 2011;Hassan & Daniel 2019;Benbow et al 2019). Finally, it has been long hypothesized that magnetar crustal activity may result in burst gravitational wave emission (Ramaty et al 1980).…”

Section: Predictions and Observational Tests Of The Low-twist Magnetamentioning

confidence: 99%

The Fast Radio Burst Luminosity Function and Death Line in the Low-twist Magnetar Model

Wadiasingh

Beniamini

Timokhin

et al. 2020

ApJ

View full text Add to dashboard Cite

We explore the burst energy distribution of fast radio bursts (FRBs) in the low-twist magnetar model of Wadiasingh & Timokhin (2019). Motivated by the power-law fluence distributions of FRB 121102, we propose an elementary model for the FRB luminosity function of individual repeaters with an inversion protocol which directly relates the power-law distribution index of magnetar short burst fluences to that for FRBs. The protocol indicates the FRB energy scales virtually linearly with crust/field dislocation amplitude, if magnetar short bursts prevail in the magnetoelastic regime. Charge starvation in the magnetosphere during bursts (required in WT19) for individual repeaters implies the predicted burst fluence distribution is narrow, < ∼ 3 decades for yielding strains and oscillation frequencies feasible in magnetar crusts. Requiring magnetic confinement and charge starvation, we obtain a death line for FRBs which segregates magnetars from the normal pulsar population, suggesting only the former will host FRBs. We convolve the burst energy distribution for individual magnetars to define the distribution of luminosities in evolved magnetar populations. The broken power-law luminosity function's low energy character depends on the population model, while the high energy index traces that of individual repeaters. Independent of the evolved population, the broken power-law isotropic-equivalent energy/luminosity function peaks at ∼ 10 38 − 10 40 erg with a sharp low-energy cutoff at < ∼ 10 37 erg. Lastly, we consider the local fluence distribution of FRBs, and find that it can constrain the subset of FRB-producing magnetar progenitors. Our model suggests that improvements in sensitivity may reveal flattening of the global FRB fluence distribution and saturation in FRB rates. 1/7 c and ε CR,pp ∝ ρ 1/2 c . There also exist regimes between B ∼ 10 13 − 10 14 G where the splitting length may be shorter than the pair length, owing to the dependence of splitting amplitude integrals M σ on B (for details, see Hu et al. 2019). A more complete study of pair cascades with splitting for FRB models is deferred to the future.

show abstract

Section: Predictions and Observational Tests Of The Low-twist Magnetamentioning

confidence: 99%

The Fast Radio Burst Luminosity Function and Death Line in the Low-twist Magnetar Model

Wadiasingh

Beniamini

Timokhin

et al. 2020

ApJ

View full text Add to dashboard Cite

show abstract

“…The dots indicate the instantaneous baseline coverage of the VERITAS SII system pointing at zenith, the blue shaded regions show the phase space that could be covered by a comparable CTA SII system. The stars are the stellar diameter measurements made from asteroid occultation observations made by VERITAS [10].…”

Section: Discussionmentioning

confidence: 99%

“…Optical observations can either make use of the existing focal plane instrumentation infrastructure, e.g. [9,10,11,21], or be externally mounted on to the camera housing, as in [12,13]. Most uses of Cherenkov telescopes in the optical regime, however, have concentrated on measurements of the Crab optical pulsar signal either to calibrate the timing systems of these instruments for γ-ray pulsar searches [14,15,16,17,18,19,20,21,13].…”

Section: An Historical Perspectivementioning

confidence: 99%

“…Even though the relative 100% drop in starlight intensity from the occultation is nominally in excess of that for the eclipsing binary, the much smaller initial intensity of the 10th magnitude star being observed (∼2 visual magnitudes below the night sky background contribution to the pixel current) means the signal of the occultation is at/below the resolution of the standard VERITAS focal plane current monitoring system [9], but it is well within the capabilities of even an off-the-shelf datalogger like the DATAQ D-710-ELS used in the enhancement to detect both the occultation and the fringes of the diffracted starlight (which cause a maximum intensity brightening of 40% of the starlight in the first diffraction fringe for a point-like source). The deviation of the fringe profile from that expected for a point-like source enabled these Cherenkov telescopes to directly measure the angular diameter of stars to≤ 0.1 mas) [10,26] for the highest angular resolution measurements made in the optical regime (visual wavebands) to date (and at a level ∼ 10 6 orders of magnitude smaller than the IACT design point spread function (≈ 0.1 • ). There are several aspects that can constrain the achievable limit on angular resolution (φ m ) from observing an occultation in the Fresnel diffraction approximation region [23]:…”

Section: Eclipses Occultations and Transitsmentioning

confidence: 99%

“…Light [34,42] or asteroid occultation [10] observations. The colour scale for the stars matches the spectral classification, but not necessarily the luminosity classification for the star.…”

Section: Pos(icrc2019)007mentioning

confidence: 99%

See 2 more Smart Citations

Non-Gamma-ray Applications of TeV Telescopes

Daniel¹

2019

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019)

View full text Add to dashboard Cite

Imaging Atmospheric Cherenkov Telescopes (IACTs) are instruments for the indirect detection of very high energy cosmic and gamma rays, since they are essentially very large light buckets used to gather the optical Cherenkov photons generated within extensive air showers. Whilst the imaging quality of their reflective surfaces may be crude it should not be forgotten that they are in actuality amongst the largest optical telescopes ever constructed-with sensitive camera equipment ideal for application to high time resolution optical astronomical research from scales of seconds down to nanoseconds. Recent advances in instrumentation have resulted in the VER-ITAS IACTs making sub-milliarcsecond resolution observations through the revived technique of intensity interferometry and obtaining the smallest optical angular resolution measurements to date in direct measurements of stellar diameters at the ∼100 micro-arcsecond scale from observations of asteroid occultations of stars. There are many further diverse non-gamma-ray applications that these types of telescopes are starting to contribute to: from the simultaneous search for optical counterparts to Fast Radio Bursts, to the search for extraterrestrial intelligence. This increased range of utility for these form of telescope expands their potential remit from facilities for specialised purposes to observatories for a wider scientific community in prime locations around the world.

show abstract

The Major Gamma-Ray Imaging Cherenkov Telescopes (MAGIC)

Blanch

Sitarek

2023

Handbook of X-Ray and Gamma-Ray Astrophysics

View full text Add to dashboard Cite

Direct measurement of stellar angular diameters by the VERITAS Cherenkov telescopes

Cited by 23 publications

References 35 publications

The Fast Radio Burst Luminosity Function and Death Line in the Low-twist Magnetar Model

The Fast Radio Burst Luminosity Function and Death Line in the Low-twist Magnetar Model

Non-Gamma-ray Applications of TeV Telescopes

The Major Gamma-Ray Imaging Cherenkov Telescopes (MAGIC)

Contact Info

Product

Resources

About