Further calibration of the Swift ultraviolet/optical telescope

Breeveld, A. A.; Curran, P. A.; Hoversten, E. A.; Koch, S.; Landsman, W. B.; Marshall, F. E.; Page, M. J.; Poole, T.; Roming, P. W. A.; Smith, Phil; Still, M.; Yershov, V. N.; Blustin, A. J.; Brown, P. J.; Grönwall, C.; Holland, S. T.; Kuin, N. P. M.; McGowan, K.; Rosen, S. R.; Boyd, Patricia T.; Broos, P. S.; Carter, M.; Chester, M. M.; Hancock, B.; Huckle, H.; Immler, S.; Ivanushkina, M.; Kennedy, T.; Mason, K. O.; Morgan, A. N.; Oates, S. R.; Pasquale, M. de; Schady, P.; Siegel, M. H.; Berk, Daniel Vanden

doi:10.1111/j.1365-2966.2010.16832.x

Cited by 166 publications

(73 citation statements)

References 22 publications

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“…For these two steps we use the HEAsoft software tasks uvotimsum and uvotsource, respectively. The counts were then converted to AB magnitudes and fluxes using the most recent UVOT calibrations (Poole et al 2008;Breeveld et al 2010). Altogether, we obtained 50 epochs of Swift observations from MJD 58249.8 (+32 d) to MJD 58661.4 (+444 d).…”

Section: Swift Photometrymentioning

confidence: 99%

To TDE or not to TDE: the luminous transient ASASSN-18jd with TDE-like and AGN-like qualities

Neustadt

Holoien

Kochanek

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We present the discovery of ASASSN-18jd (AT 2018bcb), a luminous optical/UV/Xray transient located in the nucleus of the galaxy 2MASX J22434289-1659083 at z = 0.1192. Swift UVOT photometry shows the UV SED of the transient to be well modeled by a slowly shrinking blackbody with temperature T ∼ 2.5 × 10 4 K, a maximum observed luminosity of L max = 4.5 +0.6 −0.3 ×10 44 erg s −1 , and a total radiated energy of E = 9.6 +1.1 −0.6 × 10 51 erg. X-ray data from Swift XRT and XMM-Newton show a transient, variable X-ray flux with blackbody and power-law components. Optical spectra show strong, roughly constant broad Balmer emission as well as transient features attributable to He ii, N iii-v, O iii, and coronal Fe. While ASASSN-18jd shares similarities with Tidal Disruption Events (TDEs), it is also similar to the "rapid turn-on" events seen in quiescent galaxies and in faint Active Galactic Nuclei (AGNs).

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Section: Swift Photometrymentioning

confidence: 99%

To TDE or not to TDE: the luminous transient ASASSN-18jd with TDE-like and AGN-like qualities

Neustadt

Holoien

Kochanek

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…The UVOT detector is a microchannel plate intensified CCD that operates in a photon counting mode. As a result, bright sources can suffer from coincidence loss (as described in Poole et al 2008;Breeveld et al 2010). The objects in our sample are too faint for this to become a significant issue, as discussed in Section 3.2.…”

Section: Sdss-iv/manga and Swift/uvotmentioning

confidence: 97%

“…Coincidence loss occurs when two or more photons arrive at a similar location within the same frame, and their pile-up can affect the measured count rate. While Breeveld et al (2010) describe coincidence loss when a point source is in front of some diffuse background source (e.g., knots of star formation on top of diffuse galactic background), the spatial resolution of our data (∼ 2 kpc) does not allow us to resolve individual H II regions. Therefore, that method is not appropriate; instead, we approached this problem using the prescription in Poole et al (2008).…”

Section: Swift/uvot Data Processingmentioning

confidence: 97%

A cautionary tale of attenuation in star-forming regions

Molina

Ajgaonkar

Yan

et al. 2020

Monthly Notices of the Royal Astronomical Society

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The attenuation of light in star forming galaxies is correlated with a multitude of physical parameters including star formation rate, metallicity and total dust content. This variation in attenuation is even more prevalent on the kiloparsec scale, which is relevant to many current spectroscopic integral field unit surveys. To understand the cause of this variation, we present and analyse Swift/UVOT near-UV (NUV) images and SDSS/MaNGA emission-line maps of 29 nearby (z < 0.084) star forming galaxies. We resolve kiloparsec-sized star forming regions within the galaxies and compare their optical nebular attenuation (i.e., the Balmer emission line optical depth, τ l B ≡ τ Hβ − τ Hα ) and NUV stellar continuum attenuation (via the NUV power-law index, β) to the attenuation law described by Battisti et al. The data agree with that model, albeit with significant scatter. We explore the dependence of the scatter of the β-τ l B measurements from the star forming regions on different physical parameters, including distance from the nucleus, star formation rate and total dust content. Finally, we compare the measured τ l B and β between the individual star forming regions and the integrated galaxy light. We find a strong variation in β between the kiloparsec scale and the larger galaxy scale not seen in τ l B . We conclude that the sight-line dependence of UV attenuation and the reddening of β due to the light from older stellar populations could contribute to the β-τ l B discrepancy.

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“…To search for a coincident source we used the Swift UVOTSOURCE tool. We set a significance of 3σ to distinguish between a detection and an upper limit (see Breeveld et al 2010). …”

Section: Swift Broadband Follow-up Analysismentioning

confidence: 99%

Searching the INTEGRAL WEAK alert population for Gamma-ray Bursts and other high energy transients

Higgins¹,

Starling²,

Götz³

et al. 2017

Proceedings of 11th INTEGRAL Conference Gamma-Ray Astrophysics in Multi-Wavelength Perspective — PoS(INTEGRAL2016)

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We investigate the nature of WEAK alerts, when the instruments detect an event that falls below the regular significance thresholds. We have initiated rapid follow-up observations of a sample of these alerts using the Swift satellite to allow for a broadband analysis of the alerts. Out of 15 chosen WEAK alert triggers (≈ 4% of the entire WEAK trigger population) we confirm the existence of six GRBs and, additionally, one candidate AGN. We have shown that real high energy events exist within the INTEGRAL WEAK alert population. Future investigations into WEAK alerts could further explore the low fluence regime for explosive transients and give direction for future gamma-ray missions.

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Further calibration of the Swift ultraviolet/optical telescope

Cited by 166 publications

References 22 publications

To TDE or not to TDE: the luminous transient ASASSN-18jd with TDE-like and AGN-like qualities

To TDE or not to TDE: the luminous transient ASASSN-18jd with TDE-like and AGN-like qualities

A cautionary tale of attenuation in star-forming regions

Searching the INTEGRAL WEAK alert population for Gamma-ray Bursts and other high energy transients

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