Activity from Magnetar Candidate 4U 0142+61: Bursts and Emission Lines
Bibliographic record
Abstract
After 6 years of quiescence, Anomalous X-ray Pulsar (AXP) 4U 0142+61 entered an active phase in 2006 March that lasted several months. During the active phase, several bursts were detected, and many aspects of the X-ray emission changed. We report on the discovery of six X-ray bursts, the first ever seen from this AXP in ~10 years of Rossi X-ray Timing Explorer (RXTE) monitoring. All the bursts occurred in the interval between 2006 April 6 and 2007 February 7. The bursts had the canonical fast rise slow decay profiles characteristic of SGR/AXP bursts. The burst durations ranged from 8-3x10^3 s as characterized by T90,these are very long durations even when compared to the broad T90 distributions of other bursts from SGRs and AXPs. The first five burst spectra are well modeled by simple blackbodies, with temperature kT ~2-6 keV. However, the sixth burst had a complicated spectrum consisting of at least three emission lines with possible additional emission and absorption lines. The most significant feature was at ~14 keV. Similar 14-keV spectral features were seen in bursts from AXPs 1E 1048.1-5937 and XTE J1810-197. If this feature is interpreted as a proton cyclotron line, then it supports the existence of a magnetar-strength field for these AXPs. Several of the bursts were accompanied by a short-term pulsed flux enhancement. We discuss these events in the context of the magnetar model.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".