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Spectroscopic confirmation of high-amplitude eruptive YSOs and dipping giants from the VVV survey
(2024-02-01)
During the pre-main-sequence (pre-MS) evolution stage of a star, significant amounts of stellar mass are accreted during episodic accretion events, such as multidecade FUor-type outbursts. Here, we present a near-infrared ...
On the incidence of episodic accretion in Class I YSOs from VVV
(2024-02-01)
Episodic accretion is one of the competing models to explain the observed luminosity spread in young stellar clusters. These short-lived high accretion events could also have a strong impact on planet formation. Observations ...
The most variable VVV sources: eruptive protostars, dipping giants in the Nuclear Disc and others
(2024-02-01)
We have performed a comprehensive search of a VISTA Variables in the Via Lactea (VVV) data base of 9.5 yr light curves for variable sources with ΔKs ≥ 4 mag, aiming to provide a large sample of high amplitude eruptive young ...
Long-period Radio Pulsars: Population Study in the Neutron Star and White Dwarf Rotating Dipole Scenarios
(2024-02-01)
The nature of two recently discovered radio emitters with unusually long periods of 18 minutes (GLEAM-X J1627-52) and 21 minutes (GPM J1839-10) is highly debated. Their bright radio emission resembles that of radio magnetars, ...
Mitigating Modal Noise in Multimode Circular Fibres by Optical Agitation using a Galvanometer
(2024-01-02)
Modal noise appears due to the non-uniform and unstable distribution of light intensity among the finite number of modes in multimode fibres. It is an important limiting factor in measuring radial velocity precisely by ...
Ultracool Spectroscopic Outliers in Gaia DR3
(2024-01-01)
Gaia DR3 provided a first release of RP spectra and astrophysical parameters for ultracool dwarfs (UCDs). We used these Gaia RP spectra and astrophysical parameters to select the most outlying UCDs. These objects have ...
New Eruptive YSOs from SPICY and WISE
(2023-12-28)
This work presents four high-amplitude variable YSOs (≃3 mag at near-or mid-IR wavelengths) arising from the SPICY catalog. Three outbursts show a duration that is longer than 1 year, and are still ongoing. And additional ...
A Benchmark White Dwarf-Ultracool Dwarf Wide Field Binary
(2023-12-19)
We present the discovery and multi-wavelength characterisation of VVV J1438-6158 AB, a new field wide-binary system consisting of a 4.6(+5.5-2.4) Gyr and Teff = 9500+/-125 K DA white dwarf (WD) and a Teff = 2400+/-50 K M8 ...
Gaia21bty: An EXor light curve exhibiting a FUor spectrum
(2023-10-30)
Gaia21bty, a pre-main sequence star that previously had shown aperiodic dips in its light curve, underwent a considerable Delta G~2.9 mag brightening that occurred over a few months between 2020 October - 2021 February. ...
Plausible association of distant late M dwarfs with low-frequency radio emission
(2023-10-17)
We present the serendipitous discovery of eight distant (> 50 pc) late M dwarfs with plausible associated radio emission at 144 MHz. The M-dwarf nature of our sources has been confirmed with optical spectroscopy performed ...