Quasi-periodic X-ray eruptions years after a nearby tidal disruption event.

Quasi-periodic eruptions (QPEs) are luminous bursts of soft X-rays from the nuclei of galaxies, repeating on timescales of hours to weeks. The mechanism behind these rare systems is uncertain, but most theories involve accretion disks around supermassive black holes (SMBHs) undergoing instabilities or interacting with a stellar object in a close orbit. It has been suggested that this disk could be created when the SMBH disrupts a passing star, implying that many QPEs should be preceded by observable tidal disruption events (TDEs).

JWST detection of a supernova associated with GRB 221009A without an r-process signature.

Identifying the sites of r-process nucleosynthesis, a primary mechanism of heavy element production, is a key goal of astrophysics. The discovery of the brightest gamma-ray burst (GRB) to date, GRB 221009A, presented an opportunity to spectroscopically test the idea that r-process elements are produced following the collapse of rapidly rotating massive stars. Here we present James Webb Space Telescope observations of GRB 221009A obtained +168 and +170 rest-frame days after the gamma-ray trigger, and demonstrate that they are well described by a SN 1998bw-like supernova (SN) and power-law afterglow, with no evidence for a component from r-process emission.

Obstetrical and neonatal outcomes in patients with surgically repaired heart disease.

Background: Congenital and acquired heart disease complicate 1% to 4% of pregnancies in the United States. Beyond the risks of the underlying maternal congenital heart disease, cardiac surgery and its sequelae, such as surgical scarring resulting in higher rates of arrhythmias and implanted valves altering anticoagulation status, have potential implications that could affect gestation and delivery.

Objective: This study aimed to investigate whether history of maternal cardiac surgery is associated with adverse obstetrical or neonatal outcomes compared with patients without a history of cardiac disease or surgery, considered "healthy controls.

Term Neonatal Outcomes after Maternal Magnesium Sulfate Treatment for Seizure Prophylaxis.

Objective: This study aimed to evaluate term neonatal outcomes after maternal magnesium sulfate (MgSO) treatment for seizure prophylaxis.

Study Design: This was a single-site retrospective cohort study of all women with term singleton gestation requiring MgSO treatment for seizure prophylaxis and their respective neonatal outcomes from January 2013 through December 2020. Our primary outcome was neonatal intensive care unit (NICU) admission.

A kilonova following a long-duration gamma-ray burst at 350 Mpc.

Gamma-ray bursts (GRBs) are divided into two populations; long GRBs that derive from the core collapse of massive stars (for example, ref. ) and short GRBs that form in the merger of two compact objects. Although it is common to divide the two populations at a gamma-ray duration of 2 s, classification based on duration does not always map to the progenitor.

Incidence of Hypertensive Disorders of Pregnancy in Women with COVID-19.

Objective: The study aimed to examine the incidence of hypertensive disorders of pregnancy in women diagnosed with SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2, also known as COVID-19).

Study Design: This was a retrospective cohort study of all women who delivered at MedStar Washington Hospital Center in Washington, DC from April 8, 2020 to July 31, 2020. Starting April 8, 2020, universal testing for COVID-19 infection was initiated for all women admitted to labor and delivery.

Infiltrating T-cell markers in cervical carcinogenesis: a systematic review and meta-analysis.

Background: The host adaptive immune response helps determine which cervical HPV infections persist and progress to precancer and cancer, and systematic characterisation of T-cell infiltration would help inform key steps in cervical carcinogenesis.

Methods: A systematic review and meta-analysis were conducted of infiltrating T-cells in normal cervix, low-grade lesions, high-grade lesions, and invasive cancers including epithelial, stromal, and total tissue and the following markers: CD3, CD4, CD8, FoxP3, CD25, and the CD4:CD8 ratio. An additional qualitative review summarised longitudinal data on associations between infiltrating T-cells and cervical disease persistence, regression, progression, or prognosis.

Racial Disparity in Postpartum Readmission due to Hypertension among Women with Pregnancy-Associated Hypertension.

Objective: Postpartum hypertension is a leading cause of readmission in the postpartum period. We aimed to examine the prevalence of racial/ethnic differences in postpartum readmission due to hypertension in women with antepartum pregnancy-associated hypertension.

Study Design: This was a multi-institutional retrospective cohort study of all women with antepartum pregnancy-associated hypertension diagnosed prior to initial discharge from January 2009 to December 2016.

Effect of Implementing Quantitative Blood Loss Assessment at the Time of Delivery.

Objective: To evaluate the ability of estimated blood loss (EBL) and quantitative blood loss (qBL) to predict need for blood transfusion in women with postpartum hemorrhage (PPH).

Study Design: This is a retrospective chart review that identified women with PPH (>1,000 mL for vaginal or cesarean delivery) between September 2014 and August 2015, reported by EBL ( = 92), and October 2015 and September 2016, reported by qBL ( = 374). The primary metric was the area under the receiver-operating characteristic curve for blood transfusion.

X-Rays from the Location of the Double-humped Transient ASASSN-15lh.

We present the detection of persistent soft X-ray radiation with ~ 10-10 erg s at the location of the extremely luminous, double-humped transient ASASSN-15lh as revealed by and . We interpret this finding in the context of observations from our multiwavelength campaign, which revealed the presence of weak narrow nebular emission features from the host-galaxy nucleus and clear differences with respect to superluminous supernova optical spectra. Significant UV flux variability on short timescales detected at the time of the rebrightening disfavors the shock interaction scenario as the source of energy powering the long-lived UV emission, while deep radio limits exclude the presence of relativistic jets propagating into a low-density environment.

Ejection of the Massive Hydrogen-rich Envelope Timed with the Collapse of the Stripped SN 2014C.

We present multi-wavelength observations of SN 2014C during the first 500 days. These observations represent the first solid detection of a young extragalactic stripped-envelope SN out to high-energy X-rays ~40 keV. SN 2014C shows ordinary explosion parameters ( ~ 1.

Slowly fading super-luminous supernovae that are not pair-instability explosions.

Super-luminous supernovae that radiate more than 10(44) ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae.

An ultraviolet-optical flare from the tidal disruption of a helium-rich stellar core.

The flare of radiation from the tidal disruption and accretion of a star can be used as a marker for supermassive black holes that otherwise lie dormant and undetected in the centres of distant galaxies. Previous candidate flares have had declining light curves in good agreement with expectations, but with poor constraints on the time of disruption and the type of star disrupted, because the rising emission was not observed. Recently, two 'relativistic' candidate tidal disruption events were discovered, each of whose extreme X-ray luminosity and synchrotron radio emission were interpreted as the onset of emission from a relativistic jet.

Light echoes reveal an unexpectedly cool η Carinae during its nineteenth-century Great Eruption.

η Carinae is one of the most massive binary stars in the Milky Way. It became the second-brightest star in our sky during its mid-nineteenth-century 'Great Eruption', but then faded from view (with only naked-eye estimates of brightness). Its eruption is unique in that it exceeded the Eddington luminosity limit for ten years.

Birth of a relativistic outflow in the unusual γ-ray transient Swift J164449.3+573451.

Active galactic nuclei, which are powered by long-term accretion onto central supermassive black holes, produce relativistic jets with lifetimes of at least one million years, and the observation of the birth of such a jet is therefore unlikely. Transient accretion onto a supermassive black hole, for example through the tidal disruption of a stray star, thus offers a rare opportunity to study the birth of a relativistic jet. On 25 March 2011, an unusual transient source (Swift J164449.

Supernova 2007bi as a pair-instability explosion.

Stars with initial masses such that 10M[symbol: see text] or= 140M[symbol: see text] (if such exist) develop oxygen cores with masses, M(core), that exceed 50M[symbol: see text], where high temperatures are reached at relatively low densities.

An unusually fast-evolving supernova.

Analyses of supernovae (SNe) have revealed two main types of progenitors: exploding white dwarfs and collapsing massive stars. Here we describe SN 2002bj, which stands out as different from any SN reported to date. Its light curve rose and declined very rapidly, yet reached a peak intrinsic brightness greater than -18 magnitude.

The binary progenitor of Tycho Brahe's 1572 supernova.

The brightness of type Ia supernovae, and their homogeneity as a class, makes them powerful tools in cosmology, yet little is known about the progenitor systems of these explosions. They are thought to arise when a white dwarf accretes matter from a companion star, is compressed and undergoes a thermonuclear explosion. Unless the companion star is another white dwarf (in which case it should be destroyed by the mass-transfer process itself), it should survive and show distinguishing properties.