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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"

41728 results found.

  1. GRB040825A: Optical observations
  2. GRB040825A: Optical observations
  3. GRB 040827: optical and NIR observations at the VLT
  4. GRB 040827: UKIRT - 2nd epoch K-band imaging
  5. GRB 040827: 2nd epoch of Magellan K-band imaging
  6. GRB 040827: K imaging - no evidence of variability
  7. GRB 040827: Detection of NIR afterglow
  8. GRB 040827: Possible detection of optical afterglow
  9. GRB 040827: RTT150 optical observations
  10. GRB040827 XMM-Newton observation
  11. MASTER: GRB040827 possible OT
  12. GRB 040825B: Optical observations
  13. GRB040827 optical observations
  14. GRB 040827 - Refined position
  15. GRB 040827 : peak flux
  16. GRB 040827 - A long GRB detected by INTEGRAL
  17. GRB040825B, BVRcIc field photometry
  18. GRB040825A, BVRcIc field photometry
  19. GCN GRB OBSERBATION REPORT
  20. Increase of SGR 1806-20 activity
  21. GRB040825A: optical observations
  22. GRB040825B: optical observations
  23. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  24. GRB040825B: Correction to GCN 2657
  25. GRB 040825: Optical observations
  26. XRF040812: possible afterglow second Chandra observation
  27. GRB 040812: Second epoch CXO Observations
  28. GRB040823,optical observation
  29. XRF040812: GMRT observations
  30. XRF 040812: optical observation at VLT
  31. GRB 040812: Optical counterparts of CXO sources
  32. XRF040812: possible afterglow
  33. CXO observation of GRB 040812
  34. Bursting activity from SGR 1806-20 detected with IBAS
  35. IPN/HETE localizations of GRB040810 (=H3489)
  36. GRB 040812: Keck and LCO optical observations
  37. GRB 040812: Keck and LCO observations
  38. GRB 040812: radio observations
  39. GRB040812, optical/IR observations
  40. GRB 040812: a long GRB detected by INTEGRAL
  41. GRB 040810: Optical observations of a limited region
  42. XRF040701: Optical Observations at ESO
  43. IPN/HETE triangulation of GRB040802 (=H3485)
  44. GRB 040730, infrared observations
  45. GRB 040730: Optical observations
  46. GRB 040730: a long GRB detected with INTEGRAL
  47. Ongoing activity of SGR 1806-20
  48. GRB040624: optical monitoring at TNG
  49. XRF 040701 - optical observations of the decaying Chandra source
  50. XRF040701: Second-Epoch Chandra Observations
  51. XRF040701: VLA Observations
  52. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  53. XRF040701: First-Epoch Chandra Observations
  54. GRB040709 J,H-band observations
  55. GRB040624, optical observations
  56. GRB040706:observation at University of Miyazaki
  57. XRF 040701, optical observations
  58. GRB 040624: optical observations
  59. Optical Observations of GRB040624
  60. GRB 040624: optical observations at TNG and VLT
  61. GRB 040624: R-band observations
  62. GRB 040624, optical observations
  63. GRB 040624 - A long GRB detected with INTEGRAL
  64. GRB 030329: Rebrightening of hyperluminal ejecta.
  65. IPN Summary of SGR1806-20 Activity in 2004
  66. GRB040511: Retraction of redshift identification
  67. SGR 1806-20: no IR variability of the proposed counterparts
  68. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  69. SGR 1806-20, potential NIR counterpart
  70. Activivty of SGR 1806-20
  71. GRB 040511, very fast decay?
  72. GRB 030324: Detection and Color of Host Galaxy
  73. GRB 040511: NIR observations with REM
  74. GRB040511: Redshift identifcation
  75. GRB 040511: Optical limit
  76. GRB040511: Candidate optical/NIR afterglow
  77. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  78. GRB 040511: Second Epoch Optical Observations
  79. GRB 040511: Optical observations
  80. GRB 040511: Optical Observations
  81. GRB040511: Optical Observations
  82. GRB040511: Optical Observations
  83. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  84. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  85. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  86. IPN triangulation of GRB040425 (=H3183)
  87. On Line Availability of Archival HETE Fregate Data and Lightcurves
  88. GRB040422: optical observations at Xinglong Observatory
  89. GRB 040423 (=H3175): A Long GRB Localized by HETE
  90. GRB040422, optical observations at Loiano
  91. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  92. GRB040422, BVRcIc field calibration
  93. GRB 040422,optical observation
  94. GRB040422: optical and NIR observations at the VLT
  95. GRB 040422: a long GRB detected with INTEGRAL
  96. GRB 040403, deep optical observations
  97. INTEGRAL-SPI/ACS GRB data: timing correction
  98. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  99. GRB 040403: Optical Observations
  100. GRB 040403 Optical Observations

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