| 1. |
- Andreoni, I., et al.
(författare)
-
Follow Up of GW170817 and Its Electromagnetic Counterpart by Australian-Led Observing Programmes
- 2017
-
Ingår i: Publications Astronomical Society of Australia. - : Cambridge University Press (CUP). - 1323-3580 .- 1448-6083. ; 34
-
Forskningsöversikt (refereegranskat)abstract
- The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (similar to 2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
|
|
| 2. |
- Schiller, D, et al.
(författare)
-
The Human Affectome
- 2024
-
Ingår i: Neuroscience and biobehavioral reviews. - 1873-7528. ; 158, s. 105450-
-
Tidskriftsartikel (refereegranskat)
|
|
| 3. |
- Semb, G, et al.
(författare)
-
Erratum
- 2017
-
Ingår i: Journal of plastic surgery and hand surgery. - 2000-6764. ; 51:2, s. 158-158
-
Tidskriftsartikel (refereegranskat)
|
|
| 4. |
- Kasliwal, M. M., et al.
(författare)
-
Illuminating gravitational waves : A concordant picture of photons from a neutron star merger
- 2017
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 358:6370, s. 1559-
-
Tidskriftsartikel (refereegranskat)abstract
- Merging neutron stars offer an excellent laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of an electromagnetic counterpart (EM170817) with gravitational waves (GW170817) detected from merging neutron stars. By synthesizing a panchromatic data set, we demonstrate that merging neutron stars are a long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma rays seen in EM170817 are dissimilar to classical short gamma-ray bursts with ultrarelativistic jets. Instead, we suggest that breakout of a wide-angle, mildly relativistic cocoon engulfing the jet explains the low-luminosity gamma rays, the high-luminosity ultraviolet-optical-infrared, and the delayed radio and x-ray emission. We posit that all neutron star mergers may lead to a wide-angle cocoon breakout, sometimes accompanied by a successful jet and sometimes by a choked jet.
|
|
| 5. |
|
|
| 6. |
- Vigren, E., et al.
(författare)
-
Collision-induced dissociation of ∼2-MeV O+3 and N+3 ions
- 2013
-
Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 87:5
-
Tidskriftsartikel (refereegranskat)abstract
- We present a study into the collision-induced dissociation (possibly including electron stripping) of O-3(+) and N-3(+) with rest gas molecules (predominantly H-2) in the heavy-ion storage ring CRYRING. The projectile ions had kinetic energies of 1.96 MeV (O-3(+)) and 2.25 MeV (N-3(+)) and from the experimental data we could derive the relative importance of the channels that produce at least one neutral product fragment. The dominant type of fragmentation for both ions involves the production of a single neutral fragment, namely an individual atom. We also find pronounced dissimilarities when comparing the O-3(+) and N-3(+) results, which we link to the stronger chemical bonds in the nitrogen system.
|
|
| 7. |
- Fogle, M., et al.
(författare)
-
Electron-impact dissociation of XH2+ (X = B, C, N, O, F) : Absolute cross sections for production of XH+ and X+ fragment ions
- 2010
-
Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 82:4, s. 042720-
-
Tidskriftsartikel (refereegranskat)abstract
- Absolute cross sections for electron-impact dissociation of XH2+ (X = B, C, N, O, F) producing XH+ and X+ ion fragments were measured in the 3- to 100-eV range using a crossed-electron-ion beams technique. Dissociative excitation of BD2+ and CH2+ producing B+ and C+, respectively, show a propensity toward a two-body dissociation while the remaining species all tend to show a three-body dissociation dynamic. The BD+ and CH+ dissociative excitation channels show a large resonant-type contribution to the cross sections at similar to 10eV. For the X+ fragment ion production cross sections, a clear dependence on the threshold energy, as it relates to the rate of rise in the cross section above threshold, is observed.
|
|
| 8. |
- Fogle, M., et al.
(författare)
-
Electron-impact dissociative excitation and ionization of N(2)D(+)
- 2011
-
Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 84:3, s. 032714-
-
Tidskriftsartikel (refereegranskat)abstract
- Absolute cross sections for electron-impact dissociation of N(2)D(+) producing N(2)(+), ND(+), and N(+) ion fragments were measured in the 5- to 100-eV range using a crossed electron-ion beams technique. In the 5- to 20-eV region, in which dissociative excitation (DE) is the principal contributing mechanism, N(2)(+) production dominates. The N(2)(+) + D dissociation channel shows a large resonant-like structure in the DE cross section, as observed previously in electron impact dissociation of triatomic dihydride species [M. Fogle, E. M. Bahati, M. E. Bannister, S. H. M. Deng, C. R. Vane, R. D. Thomas, and V. Zhaunerchyk, Phys. Rev. A 82, 042720 (2010)]. In the dissociative ionization (DI) region, 20- to 100-eV, N(2)(+), ND(+), and N(+) ion fragment production are comparable. The observance of the ND(+) and N(+) ion fragments indicate breaking of the N-N bond along certain dissociation channels.
|
|
| 9. |
- Fogle, M., et al.
(författare)
-
Electron-impact ionization of Be-like CIII, NIV, and OV
- 2008
-
Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 175:2, s. 543-556
-
Tidskriftsartikel (refereegranskat)abstract
- We present recent measurements of absolute electron-impact ionization cross sections for Be-like C III, N IV, and O V forming Li- like C IV, N V, and O VI. The measurements were taken using the crossed-beams apparatus at Oak Ridge National Laboratory. A gas cell beam attenuation method was used to independently measure the metastable fractions present in the ion beams. The measured ionization cross sections were compared with calculations using the R-matrix with pseudostates and distorted-wave theoretical methods. Best agreement is found with the R-matrix with pseudostates cross sections results that account for the metastable fractions inferred from the gas attenuation measurements. We present a set of recommended rate coefficients for electron-impact single ionization from the ground state and metastable term of each ion.
|
|
| 10. |
|
|
