Could Segue 1 be a destroyed star cluster? – a dynamical perspective

Domínguez, Raimundo; Fellhauer, M.; Blaña, M.; Farias, J. P.; Dabringhausen, J.; Candlish, Graeme N.; Smith, Rory; Choque, N.

doi:10.1093/mnras/stw1559

Cited by 15 publications

(20 citation statements)

References 27 publications

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“…Therefore, we accept the null hypothesis H 0 for any values in the region (m a , g 12 ) ∈ [0.1 neV, 2.5 neV ] × [2. 9,40]. This result demonstrates that the gamma-ray observations of distant blazars prefer the null hypothesis H 0 , i.e., the Gilmore EBL model.…”

Section: B the Best Modelmentioning

confidence: 53%

“…In this process, the ALP parameters for every spectrum-fitting are in common and in the parameter region (m a , g 12 ) ∈ [0.1 neV, 2.5 neV ] × [2. 9,40]. It can be probed by the planed IAXO experiment and the part of g 12 < 5 is outside the excluded region constrained by gamma-ray observations (SN1987A and Fermi/LAT NGC1275).…”

Section: B Intrinsic Spectra and Methodsmentioning

confidence: 98%

“…Refs. [8][9][10][11][12][13]). Another technique to constrain the EBL indirectly is based on the γ-ray observations of extragalactic sources.…”

Section: Introductionmentioning

confidence: 99%

“…Refs. [8][9][10][11][12][13], by comparing the difference between the assumed-intrinsic spectra and the observed one. Thanks to the discovery of more and more distant Tev blazars, several groups have detected this imprint, e.g.…”

mentioning

confidence: 99%

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Testing the CIBER cosmic infrared background measurements and axionlike particles with observations of TeV blazars

et al. 2020

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The first measurements from the CIBER experiment of extragalactic background light (EBL) in near-infrared (NIR) band exhibit a higher intensity than those inferred through γ-ray observations. Recent theoretical-EBL intensities are typically consistent with the very high energy (VHE) γ-ray observations. Yet, it is possible that the excess NIR radiation is a new component of EBL and not in tension with the TeV spectra of distant blazars, since the hypothetical axion-like particle (ALP) may lead to a reduced opacity of the Universe for VHE γ-rays. In order to probe whether the excess component arises mainly from EBL, thirteen observed spectra in high energy and VHE ranges from ten distant TeV BL Lac objects are fitted by four theoretical spectra which involve theoretical EBL (Gilmore ), Gilmore's EBL model including photon/ALP coupling, Gilmore's EBL with CIBER excess and the latter including photon/ALP coupling respectively. We find the goodness of fit for the model with CIBER excess can be improved with a significance of 7.6 σ after including the photon/ALP coupling; Thus, the ALP/photon mixing mechanism can effectively alleviate the tension; However, the Gilmore EBL model, on the whole, is more compatible with the observed spectra compared to those with ALP, although individual blazars such as PKS 1424+240 and 1ES 1101-232 prefer the ALP-model. Our results suggest that the recent EBL models can solely explain the VHE γ-ray observations, and assuming the existence of the ALP to alleviate the tension is not required in a statistical sense, thus the excess over the EBL models is less likely to be a new EBL component. * EBL intensities (for reviews see e.g. Refs. [1,16,17]) and test the empirical EBL models, e.g. Refs. [8][9][10][11][12][13], by comparing the difference between the assumed-intrinsic spectra and the observed one. Thanks to the discovery of more and more distant Tev blazars, several groups have detected this imprint, e.g. Refs. [15,18,19], and found the intensities were near the galaxy-count lower limits.The spectra of a few individual blazars such as PKS1424+240 appear to be unexpectedly hard [34]. Furthermore, hints for a reduced gamma-ray opacity in the form of a pair-production anomaly [20] (i.e., VHE γ-ray observations require an EBL level below the lower limits from galaxy counts), or unusual redshift-dependent intrinsic (after correction for EBL absorption) spectral hardening found in large samples, have been claimed by several authors [21][22][23][24]. However, no significant and systematic anomalies on the entire sample were revealed by recent systematic studies of spectra fitted with recent theoretical EBL absorption on large samples of VHE blazars, see e.g., 33,34]. The intensities of these recent EBL models (e.g. Franceschini 2008 [8], Dominguez 2011 [9], Kneiske 2010 [10], Finke 2010 [11], Gilmore 2012 [12], Stecker 2016 [13]) are close to that from the galaxy counts. At present, many EBL measurements inferred by γ-ray observations reveal that its intensities are generally consistent with ...

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Section: B the Best Modelmentioning

confidence: 53%

Section: B Intrinsic Spectra and Methodsmentioning

confidence: 98%

“…Refs. [8][9][10][11][12][13]). Another technique to constrain the EBL indirectly is based on the γ-ray observations of extragalactic sources.…”

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Testing the CIBER cosmic infrared background measurements and axionlike particles with observations of TeV blazars

et al. 2020

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“…In spite of that, only a few attempts have been made to study the axion effects on the evolution of stars a few times heavier than the sun. Dominguez et al (1999) The axion luminosity is given by:…”

Section: Axion Impact On Massive Starsmentioning

confidence: 99%

The Initial Mass–Final Luminosity Relation of Type II Supernova Progenitors: Hints of New Physics?

Straniero

Domínguez

Piersanti

et al. 2019

ApJ

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We revise the theoretical initial mass-final luminosity relation for progenitors of type IIP and IIL supernovae. The effects of the major uncertainties, as those due to the treatment of convection, semiconvection, rotation, mass loss, nuclear reaction rates and neutrinos production rates are discussed in some details.The effects of mass transfer between components of close-binary systems are also considered. By comparing the theoretical predictions to a sample of type II supernovae for which the initial mass of the progenitors and the pre-explosive luminosity are available, we conclude that stellar rotation may explain a few progenitors which appear brighter than expected in case of non-rotating models. In the most extreme case, SN2012ec, an initial rotational velocity up to 300 km s −1 is required. Alternatively, these objects could be mass-loosing components of close binaries. However, most of the observed progenitors appear fainter than expected. This occurrence seems to indicate that the Compton and pair neutrino energy-loss rates, as predicted by the standard electro-weak theory, are not efficient enough and that an additional negative contribution to the stellar energy balance is required. We show that axions coupled with parameters accessible to currently planned experiments, such as IAXO and, possibly, Baby-IAXO and ALPS II, may account for the missing contribution to the stellar energy-loss.

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Modelling the Canes Venatici I dwarf spheroidal galaxy

Carrillo

Fellhauer

Jara

et al. 2020

A&A

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The aim of this work is to find a progenitor for Canes Venatici I (CVn I), under the assumption that it is a dark matter free object that is undergoing tidal disruption. With a simple point mass integrator, we searched for an orbit for this galaxy using its current position, position angle, and radial velocity in the sky as constraints. The orbit that gives the best results has the pair of proper motions μα = −0.099 mas yr−1 and μδ = −0.147 mas yr−1, that is, an apogalactic distance of 242.79 kpc and a perigalactic distance of 20.01 kpc. Using a dark matter free progenitor that undergoes tidal disruption, the best-fitting model matches the final mass, surface brightness, effective radius, and velocity dispersion of CVn I simultaneously. This model has an initial Plummer mass of 2.47 × 107 M⊙ and a Plummer radius of 653 pc, producing a remnant after 10 Gyr with a final mass of 2.45 × 105 M⊙, a central surface brightness of 26.9 mag arcsec−2, an effective radius of 545.7 pc, and a velocity dispersion with the value 7.58 km s−1. Furthermore, it is matching the position angle and ellipticity of the projected object in the sky.

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Could Segue 1 be a destroyed star cluster? – a dynamical perspective

Cited by 15 publications

References 27 publications

Testing the CIBER cosmic infrared background measurements and axionlike particles with observations of TeV blazars

Testing the CIBER cosmic infrared background measurements and axionlike particles with observations of TeV blazars

The Initial Mass–Final Luminosity Relation of Type II Supernova Progenitors: Hints of New Physics?

Modelling the Canes Venatici I dwarf spheroidal galaxy

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