Spectrum formation in superluminous supernovae (Type I)

The near-maximum spectra of most superluminous supernovae (SLSNe) that are not dominated by interaction with a H-rich circum-stellar medium (SLSN-I) are characterized by a blue spectral peak and a series of absorption lines which have been identified as O II. SN 2011kl, associated with the ultra-long gamma-ray burst GRB111209A, also had a blue peak but a featureless optical/ultraviolet (UV) spectrum. Radiation transport methods are used to show that the spectra (not including SN 2007bi, which has a redder spectrum at peak, like ordinary SNe Ic) can be explained by a rather steep density distribution of the ejecta, whose composition appears to be typical of carbon–oxygen cores of massive stars which can have low metal content. If the photospheric velocity is ∼10 000–15 000 km s−1, several lines form in the UV. O II lines, however, arise from very highly excited lower levels, which require significant departures from local thermodynamic equilibrium to be populated. These SLSNe are not thought to be powered primarily by 56Ni decay. An appealing scenario is that they are energized by X-rays from the shock driven by a magnetar wind into the SN ejecta. The apparent lack of evolution of line velocity with time that characterizes SLSNe up to about maximum is another argument in favour of the magnetar scenario. The smooth UV continuum of SN 2011kl requires higher ejecta velocities (∼20 000 km s−1): line blanketing leads to an almost featureless spectrum. Helium is observed in some SLSNe after maximum. The high-ionization near-maximum implies that both He and H may be present but not observed at early times. The spectroscopic classification of SLSNe should probably reflect that of SNe Ib/c. Extensive time coverage is required for an accurate classification

Long optical plateau in the afterglow of the short GRB 150424A with extended emission

Context. Short-duration gamma-ray bursts (GRBs) with extended emission form a subclass of short GRBs, comprising about 15% of the short-duration sample. Afterglow detections of short GRBs are also rare (about 30%) because of their lower luminosity. Aims. We present a multiband data set of the short burst with extended emission, GRB 150424A, comprising of GROND observations, complemented with data from Swift/UVOT, Swift/XRT, HST, Keck/LRIS, and data points from the literature. The GRB 150424A afterglow shows an extended plateau phase, lasting about 8 h. The analysis of this unique GRB afterglow might shed light on the understanding of afterglow plateau emission, the nature of which is still under debate. Methods. We present a phenomenological analysis made by applying fireball closure relations and interpret the findings in the context of the fireball model. We discuss the plausibility of a magnetar as a central engine, which would be responsible for additional and prolonged energy injection into the fireball. Results. We find convincing evidence for energy injection into the afterglow of GRB 150424A. We find that a magnetar spin-down as the source for a prolonged energy injection requires that at least 4% of the spin-down energy is converted into radiation

Inhomogeneous Jets from Neutron Star Mergers: One Jet to Rule Them All

Using the resultant profiles from 3D hydrodynamic simulations of relativistic jets interacting with neutron star merger wind ejecta, we show how the inhomogeneity of energy and velocity across the jet surface profile can alter the observed afterglow lightcurve. We find that the peak afterglow flux depends sensitively on the observer’s line-of-sight, not only via the jet inclination but also through the jet rotation: for an observer viewing the afterglow within the GRB-bright jet core, we find a peak flux variability on the order < (Formula presented.) dex through rotational orientation and < (Formula presented.) dex for the polar inclination. An observed afterglow’s peak flux can be used to infer the jet kinetic energy, and where a top-hat jet is assumed, we find the range of inferred jet kinetic energies for our various model afterglow lightcurves (with fixed model parameters), covers ∼1/3 of the observed short GRB population. Additionally, we present an analytic jet structure function that includes physically motivated parameter uncertainties due to variability through the rotation of the source. An approximation for the change in collimation due to the merger ejecta mass is included and we show that by considering the observed range of merger ejecta masses from short GRB kilonova candidates, a population of merger jets with a fixed intrinsic jet energy is capable of explaining the observed broad diversity seen in short GRB afterglows

Epidemiologia da neoplasia maligna do esôfago no estado do Rio Grande do Sul - RS entre o período de 2017 a 2021: Epidemiology of malignant neoplasm of the esophagus in the state of Rio Grande do Sul - RS from 2017 to 2021

Objetivo: O presente trabalho visa realizar uma análise epidemiológica da neoplasia maligna do esôfago no Estado do Rio Grande do Sul – RS entre o período de 2017 a 2021.&nbsp; Metodologia: trata-se de um estudo epidemiológico, descritivo de abordagem quantitativa, que utilizou dados secundários obtidos no Sistema de Informação de Agravos de Notificação (SINAN). Os dados analisados foram entre o período 2017 a 2021 no Estado do Rio Grande do Sul que são agrupados por regiões de saúde, sendo elas: Verdes Campos, Entre Rios, Fronteira Oeste, Belas Praias, Bons Ventos, Paranhana, Vale dos Sinos, Vale do Caí/Metropolitana, Carbonífera/ Costa Doce, PoA/Metropolitana, Sete Povos das Missões, Portal das Missões, Região da Diversidade, Fronteira Noroeste, Caminho das Águas, Alto Uruguai Gaúcho, Região do Planalto, Região da Araucárias, Região do Botucaraí, Rota da Produção, Região Sul, Pampa, Caxias e Hortênsias, Vinhedos e Basalto , Uvas e Vales, Jacuí Centro, Santa Cruz do Sul, Vale das Montanhas, Vale da Luz. As variáveis​​ analisadas foram: números de casos, óbitos, sexo e cor dos pacientes, a faixa etária que mais apresentou casos, Caráter do atendimento, valores&nbsp;gastos com internação e média permanência na internação.&nbsp;Resultados:&nbsp;Durante os anos de 2017 a 2021 um total de 10.640 (dez mil, seiscentos e quarenta) casos de pacientes com neoplasia maligna do esôfago foram notificados em todo o Estado nos últimos 5 (cinco) anos. A região de saúde que corresponde a Capital Porto Alegre Vale do Gravataí, essas apresentaram a maioria dos casos notificados com 2.712 (dois mil, setecentos e doze). Quanto ao número de óbitos por neoplasia maligna no esôfago foram notificados 1.503 (mil e quinhentos e três). Ao analisar o sexo dos pacientes, verificou-se que a neoplasia maligna de esôfago é mais frequente entre os homens do que nas mulheres, o primeiro apresenta 7.746 (sete mil e setecentos e quarenta e seis) casos, ao passo que o segundo apresenta 2.894 (dois mil e oitocentos e noventa e quatro). À faixa etária que apresentou a maior quantidade de casos foi entre 60 a 69 anos com 3.934 (três mil novecentos e trinta e quatro casos). Os dados apontaram que, no que se refere à cor, 8.309&nbsp;se declararam como pessoas brancas.&nbsp;&nbsp;&nbsp; A taxa média de permanência de internação dos pacientes foi de 7.0 dias, com a região da Capital e Vale do Gravataí apresentando o maior tempo 9,6 dias. No que se refere aos valores&nbsp;gastos com internação, constatou-se um gasto de 17.831.327,24 (dezessete milhões oitocentos e trinta e um mil reais trezentos e vinte e sete reais e vinte quatro centavos), no período dos anos de 2017 a 2021. Por fim, as internações por caráter de atendimento na maioria dos casos se deu por urgência com 7.418 (sete mil e quatrocentos e dezoito) atendimentos. Conclusão:&nbsp; conforme apresentado ao longo da análise epidemiológica, a neoplasia maligna do esôfago constitui em causa preponderante de morbimortalidade na população Gaúcha, as elevadas estatísticas de incidência e prevalência tornam esta patologia uma constante preocupação para gestores, profissionais de saúde e população em geral

Revisiting the Long/Soft-Short/Hard Classification of Gamma-Ray Bursts in the Fermi Era

We perform a statistical analysis of the temporal and spectral properties of the latest Fermi gamma-ray bursts (GRBs) to revisit the classification of GRBs. We find that the bimodalities of duration and the energy ratio ($E_{\mathrm{peak}}$/Fluence) and the anti-correlation between spectral hardness (hardness ratio ($HR$), peak energy and spectral index) and duration ($T_{90}$) support the long/soft $-$ short/hard classification scheme for Fermi GRBs. The $HR - T_{90}$ anti-correlation strongly depends upon the spectral shape of GRBs and energy bands, and the bursts with the curved spectra in the typical BATSE energy bands show a tighter anti-correlation than those with the power-law spectra in the typical BAT energy bands. This might explain why the $HR - T_{90}$ correlation is not evident for those GRB samples detected by instruments like {\it Swift} with a narrower/softer energy bandpass. We also analyze the intrinsic energy correlation for the GRBs with measured redshifts and well defined peak energies. The current sample suggests $E_{\mathrm{p,rest}}=2455\times (E_{\mathrm{iso}}/10^{52})^{0.59}$ for short GRBs, significantly different from that for long GRBs. However, both the long and short GRBs comply with the same $E_{\mathrm{p,rest}}-L_{\mathrm{iso}}$ correlation.Comment: 17 pages, 9 figures, 4 tables. Accepted for publication in Ap

The optical/NIR afterglow of GRB 111209A: Complex yet not unprecedented

Context. Afterglows of gamma-ray bursts (GRBs) are simple in the most basic model, but can show many complex features. The ultra-long duration GRB 111209A, one of the longest GRBs ever detected, also has the best-monitored afterglow in this rare class of GRBs. Aims. We want to address the question whether GRB 111209A was a special event beyond its extreme duration alone, and whether it is a classical GRB or another kind of high-energy transient. The afterglow may yield significant clues. Methods. We present afterglow photometry obtained in seven bands with the GROND imager as well as in further seven bands with the Ultraviolet/Optical Telescope (UVOT) on-board the Neil Gehrels Swift Observatory. The light curve is analysed by multi-band modelling and joint fitting with power-laws and broken power-laws, and we use the contemporaneous GROND data to study the evolution of the spectral energy distribution. We compare the optical afterglow to a large ensemble we have analysed in earlier works, and especially to that of another ultra-long event, GRB 130925A. We furthermore undertake a photometric study of the host galaxy. Results. We find a strong, chromatic rebrightening event at ≈0.8 days after the GRB, during which the spectral slope becomes redder. After this, the light curve decays achromatically, with evidence for a break at about 9 days after the trigger. The afterglow luminosity is found to not be exceptional. We find that a double-jet model is able to explain the chromatic rebrightening. The afterglow features have been detected in other events and are not unique. Conclusions. The duration aside, the GRB prompt emission and afterglow parameters of GRB 111209A are in agreement with the known distributions for these parameters. While the central engine of this event may differ from that of classical GRBs, there are multiple lines of evidence pointing to GRB 111209A resulting from the core-collapse of a massive star with a stripped envelope

Escolisose na Síndrome de Marfan: relato de caso

Objetivo: O objetivo deste artigo é avaliar os resultados clínicos e radiográficos após a correção cirúrgica da escoliose relanatando o caso de um adolescente de 12 anos com de síndrome de Marfan diagnosticado em maio de 2022 que realizou uma cirurgia de artrodese posterior com colocação de hastes de crescimento T1/T12. Método: As informações foram obtidas através do prontuário, exames do paciente e revisão da literatura. Conclusão: O caso relatado e publicações pesquisadas colocam a discussão em foco a terapêutica de uma situação difícil que é a Síndrome de Marfan, doença multissistêmica que envolve um conjunto de sistemas como o cardiovascular, esqueléticos e olhos. As intervenções são capazes de obter um resultado satisfatório no que diz a respeito da qualidade de vida e alívio dos sintomas

The 2175 angstrom Extinction Feature in the Optical Afterglow Spectrum of GRB 180325A at z =. 2.25

The ultraviolet (UV) extinction feature at 2175 Å is ubiquitously observed in the Galaxy but is rarely detected at high redshifts. Here we report the spectroscopic detection of the 2175 Å bump on the sightline to the γ-ray burst (GRB) afterglow GRB 180325A at z = 2.2486, the only unambiguous detection over the past 10 years of GRB follow-up, at four different epochs with the Nordic Optical Telescope (NOT) and the Very Large Telescope (VLT)/X-shooter. Additional photometric observations of the afterglow are obtained with the Gamma-Ray burst Optical and Near-Infrared Detector (GROND). We construct the near-infrared to X-ray spectral energy distributions (SEDs) at four spectroscopic epochs. The SEDs are well described by a single power law and an extinction law with R V ≈ 4.4, A V ≈ 1.5, and the 2175 Å extinction feature. The bump strength and extinction curve are shallower than the average Galactic extinction curve. We determine a metallicity of [Zn/H] > −0.98 from the VLT/X-shooter spectrum. We detect strong neutral carbon associated with the GRB with equivalent width of W r(λ 1656) = 0.85 ± 0.05. We also detect optical emission lines from the host galaxy. Based on the Hα emission-line flux, the derived dust-corrected star formation rate is ~46 ± 4 M ⊙ yr−1 and the predicted stellar mass is log M */M ⊙ ~ 9.3 ± 0.4, suggesting that the host galaxy is among the main-sequence star-forming galaxies

GRB 190114C in the nuclear region of an interacting galaxy A detailed host analysis using ALMA, the HST, and the VLT

Context. For the first time, very high energy emission up to the TeV range has been reported for a gamma-ray burst (GRB). It is still unclear whether the environmental properties of GRB 190114C might have contributed to the production of these very high energy photons, or if it is solely related to the released GRB emission. Aims. The relatively low redshift of the GRB (z = 0.425) allows us to study the host galaxy of this event in detail, and to potentially identify idiosyncrasies that could point to progenitor characteristics or environmental properties that might be responsible for this unique event. Methods. We used ultraviolet, optical, infrared, and submillimetre imaging and spectroscopy obtained with the HST, the VLT, and ALMA to obtain an extensive dataset on which the analysis of the host galaxy is based. Results. The host system is composed of a close pair of interacting galaxies (Δv = 50 km s−1), both of which are well detected by ALMA in CO(3-2). The GRB occurred within the nuclear region (∼170 pc from the centre) of the less massive but more star-forming galaxy of the pair. The host is more massive (log(M/M⊙) = 9.3) than average GRB hosts at this redshift, and the location of the GRB is rather unique. The higher star formation rate was probably triggered by tidal interactions between the two galaxies. Our ALMA observations indicate that both host galaxy and companion have a high molecular gas fraction, as has been observed before in interacting galaxy pairs. Conclusions. The location of the GRB within the core of an interacting galaxy with an extinguished line of sight is indicative of a denser environment than typically observed for GRBs and could have been crucial for the generation of the very high energy photons that were observed

Short GRB 160821B: A Reverse Shock, a Refreshed Shock, and a Well-sampled Kilonova

We report our identification of the optical afterglow and host galaxy of the short-duration gamma-ray burst sGRB 160821B. The spectroscopic redshift of the host is z = 0.162, making it one of the lowest redshift short-duration gamma-ray bursts (sGRBs) identified by Swift. Our intensive follow-up campaign using a range of ground-based facilities as well as Hubble Space Telescope, XMM-Newton, and Swift, shows evidence for a late-time excess of optical and near-infrared emission in addition to a complex afterglow. The afterglow light curve at X-ray frequencies reveals a narrow jet, ${\theta }_{j}\sim {1.9}_{-0.03}^{+0.10}$ deg, that is refreshed at >1 day post-burst by a slower outflow with significantly more energy than the initial outflow that produced the main GRB. Observations of the 5 GHz radio afterglow shows a reverse shock into a mildly magnetized shell. The optical and near-infrared excess is fainter than AT2017gfo associated with GW170817, and is well explained by a kilonova with dynamic ejecta mass M dyn = (1.0 ± 0.6) × 10−3 M ⊙ and a secular (post-merger) ejecta mass with M pm = (1.0 ± 0.6) × 10−2 M ⊙, consistent with a binary neutron star merger resulting in a short-lived massive neutron star. This optical and near-infrared data set provides the best-sampled kilonova light curve without a gravitational wave trigger to date