1,987 research outputs found
The SMC X-ray transient XTE J0111.2-7317 : a Be/X-ray binary in a SNR?
We report observations which confirm the identity of the optical/IR
counterpart to the Rossi X-ray Timing Explorer transient source XTE
J0111.2-7317. The counterpart is suggested to be a B0-B2 star (luminosity class
III--V) showing an IR excess and strong Balmer emission lines. The distance
derived from reddening and systemic velocity measurements puts the source in
the SMC. Unusually, the source exhibits an extended asymetric H alpha
structure.Comment: 5 pages, 3 figs, accepted by MNRA
Sobre la posición sistemática del género Placogyropsis Alloiteau, 1957. (Scleractinia cretácica)
Utilizando varios topotipos de la especie tipo, se estudia el género Placogyropsis Alloiteau, 1957, inscrito por el propio Alloiteau en la familia Dendrogyriidae Alloiteau, 1952. Se sugiere que no pertenece a esta familia, sino a la familia Latomeandriidae y se propone una diagnosis del género
Sobre la posición sistemática del género Placogyropsis Alloiteau, 1957. (Scleractinia cretácica)
Utilizando varios topotipos de la especie tipo, se estudia el género Placogyropsis Alloiteau, 1957, inscrito por el propio Alloiteau en la familia Dendrogyriidae Alloiteau, 1952. Se sugiere que no pertenece a esta familia, sino a la familia Latomeandriidae y se propone una diagnosis del género
Bound-state dark matter with Majorana neutrinos
We propose a simple scenario in which dark matter (DM) emerges as a stable
neutral hadronic thermal relics, its stability following from an exact
symmetry. Neutrinos pick up radiatively induced
Majorana masses from the exchange of colored DM constituents. There is a common
origin for both dark matter and neutrino mass, with a lower bound for
neutrinoless double beta decay. Direct DM searches at nuclear recoil
experiments will test the proposal, which may also lead to other
phenomenological signals at future hadron collider and lepton flavour violation
experiments.Comment: 9 pages, 4 figures. arXiv admin note: text overlap with
arXiv:1803.0852
El Laboratori de física i química de l'Institut «Joan Brudieu» de la Seu d'Urgell : una perspectiva històrica
Research in a secondary school about old materials, apparatus and
methods of experimental work and teaching. This research was made by two pupils
before go to the University
A 0535+26: Back in business
In May/June 2005, after 10 years of inactivity, the Be/X-ray binary system A
0535+26 underwent a major X-ray outburst. In this paper data are presented from
10 years of optical, IR and X-ray monitoring showing the behaviour of the
system during the quiescent epoch and the lead up to the new outburst. The
results show the system going through a period when the Be star in the system
had a minimal circumstellar disk and then a dramatic disk recovery leading,
presumably, to the latest flare up of X-ray emission. The data are interpreted
in terms of the state of the disk and its interaction with the neutron star
companion.Comment: Accepted for publication in MNRA
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