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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3762 results found.

  1. GRB 180718B: Swift-XRT observations
  2. GRB 180720B: MASTER Global Net OT observations
  3. GRB 180721A: MITSuME Akeno optical upper limits
  4. GRB 180722A: MAXI/GSC detection
  5. GRB 180720B: MAXI/GSC detection
  6. GRB 180720C: LT observations
  7. GRB 180715A: MASTER optical observation
  8. GRB 180715A: Swift detection of a short hard burst
  9. IceCube-171106A: MASTER optical observation
  10. GRB 180706A: Swift-BAT refined analysis
  11. GRB 180706A: Swift detection of a burst with optical counterpart
  12. Fermi GBM triggers 552488966/180705548 and 552490104/180705561 are not GRBs
  13. GRB 180630A: Swift/UVOT Detection
  14. GRB 180630A: Swift-BAT refined analysis
  15. GRB 180626C / Fermi trigger 551697835: MASTER inspection
  16. GRB 180630A: Enhanced Swift-XRT position
  17. GRB 180630A: Swift detection of a burst with an optical counterpart
  18. IPN Triangulation of GRB 180626C (short)
  19. IPN Triangulation of GRB 180529A (short/hard)
  20. GRB 180512A: VLT/HAWK-I NIR Observations
  21. IPN Triangulation of GRB 180427A
  22. GRB 180418A: TAROT La Silla observatory early optical observations
  23. GRB 180411A: CALET Gamma-Ray Burst Monitor detection
  24. GRB 180411A: Swift detection of a burst
  25. GRB 180410A: Swift detection of a burst or a Galactic transient.
  26. IPN Triangulation of GRB 180317A (short/hard)
  27. GRB 180316A: MITSuME Akeno optical upper limits
  28. GRB 180313A: Fermi GBM detection
  29. GRB 180314A: Fermi GBM observation
  30. GRB 180314A: Swift detection of a burst with an optical counterpart
  31. GRB 180311A: Swift detection of a burst
  32. IPN Triangulation of GRB 180223A (long)
  33. GRB 180205A: Mondy optical observations
  34. GRB180205A: Optical observations with DOAO 1m telescope
  35. GRB 180205A: Further GROND Observations reveal Afterglow is still bright
  36. GRB 180205A: Mondy optical observations
  37. GRB 180205A: Swift detection of a burst with a bright optical counterpart
  38. GRB 180113B: Fermi GBM detection
  39. GRB 180102A AROMA-N optical observation
  40. GRB 171216A: Swift detection of a burst
  41. GRB 171205A: ALMA observations
  42. GRB 171210A: Swift-XRT and UVOT observations
  43. GRB 171205A: Mondy optical observations
  44. GRB 171124A: TShAO optical observations
  45. INTEGRAL pointed follow-up of IceCube-171106A
  46. IPN Triangulation of GRB 171108A (short)
  47. GRB 171010A: afterglow and SN 2017htp optical observations
  48. GRB 171108A: Fermi GBM detection
  49. GRB 171030A: MASTER inspection of the IPN error box of the short GRB.
  50. Konus-Wind observation of GRB 171103A (short/hard)
  51. Konus-Wind observation of GRB 171102A
  52. Swift Triggers 784159 and 784160 are not bursts
  53. Swift Trigger 783893 is probably not a GRB
  54. Retraction of high energy neutrino candidate IceCube-171028
  55. GRB 171010A : Optical observations from HCT
  56. GRB 171010A: LCO 1m telescope observations
  57. GRB 171010A: OT, spectrum, and possible host galaxy
  58. LIGO/Virgo G298048/GW170817: updated localization from parameter estimation
  59. LIGO/Virgo G299232: MAGIC Cherenkov Telescopes observations
  60. LIGO/Virgo G299232: LOFAR follow-up
  61. GRB 171003A: Swift detection of a burst or a Galactic Transient
  62. GRB 171001A: Nanshan-0.36m optical afterglow detections
  63. GRB 171001A: Swift detection of a burst
  64. LIGO/Virgo G298048: Record of all e-MERLIN results to date on SSS17a
  65. Correction to GCN Circular 21919: GRB 170921C: Insight-HXMT detection
  66. GRB 170921A: Swift detection of a burst
  67. LIGO/Virgo G298048: Desert Fireball Network simultaneous optical observations of the SSS17a/DLT17ck.
  68. LIGO/Virgo G298048: AST3-2 observations of SSS17a/DLT17ck from Antarctica
  69. LIGO/Virgo G297595: Las Cumbres Observatory Optical Follow-Up
  70. GRB 170906A: Swift detection of a burst with an optical afterglow
  71. LIGO/Virgo G299232: Maidanak observations of optical transient SwiftJ014008.5+343403.6
  72. LIGO/Virgo G298048: e-MERLIN upper limits on 5 GHz compact emission from SSS17a
  73. LIGO/Virgo G297595: DECam observations of BBH merger region of interest
  74. LIGO/Virgo G298048: AGILE-GRID analysis of data contemporary to X-ray emission from SSS17a in NGC4993
  75. LIGO/Virgo G298048: Hubble Space Telescope observations
  76. LIGO/Virgo G298048: Possible Plateau in Ks band revealed by continued Gemini-South observations
  77. GRB 170830A: MAXI/GSC detection
  78. LIGO/Virgo G299232: observations of the optical Transient Discovered by Swift/UVOT
  79. LIGO/Virgo G299232: COATLI Observations of MASTER OT J033744.97+723159.0
  80. LIGO/Virgo G298048: Further ATCA follow-up of SSS17a in NGC 4993
  81. LIGO/Virgo G299232: Continued observation of the transient near NGC 1343
  82. IPN Triangulation of GRB 170827B (short)
  83. LIGO/Virgo G299232 TZAC/TAROT observations
  84. GROND observations of GRB170827A
  85. GRB 170827A: ePESSTO NTT afterglow candidate
  86. LIGO/Virgo G299232/PGWB170825.55: MASTER Global-Net OT inside NGC1343 discovery
  87. GRB 170827A: Swift detection of a burst
  88. LIGO/Virgo G299232: CALET Observations
  89. LIGO/Virgo G298936: CALET Observations
  90. LIGO/Virgo G298936 TAROT/TZAC observations
  91. LIGO/Virgo G298048: LWA radio observations
  92. LIGO/Virgo G298389: CALET Observations
  93. LIGO/Virgo G298048: CALET Observations
  94. LIGO/Virgo G298048: HSC observations of the OT candidate of G298048
  95. LIGO/Virgo G298048: Archival 2MASS and Spitzer non-detections of the potential LIGO EM counterpart SSS17a
  96. LIGO/Virgo G298048: SkyMapper uvgri photometry of the candidate in NGC 4933
  97. LIGO/Virgo G298048: TZAC TAROT Reunion (TRE) observations
  98. LIGO/Virgo G298048: Subaru HSC follow-up observations
  99. LIGO/Virgo G298048: Inspection of archival HST data at the position of the potential optical counterpart
  100. LIGO/Virgo G298048: REM optical/NIR observations of candidate in NGC 4993

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