Notices levels

SVOM notices are classified according to their processing level and the instrument that produced the data:

• N1 notices correspond to the notification of a new detection by ECLAIRs (N1e) or GRM (N1g). They are generated automatically and as quickly as possible, within few seconds after a burst

• N2 notices give refined information about the detection within minutes after the burst. If the SVOM plateform performed a slew following an ECLAIRs trigger, MXT and VT perform an on-board follow-up and issue respectively N2m or N2v notices in case of a detection

In the VOEvent standard, notices are XML-formatted files uniquely identified by their IVOA Resource Name, or IVORN. The SVOM notices IVORNs format is:

ivo://org.svom/fsc#sbYYMMDDnn_notice-type

where sbYYMMDDnn is the SVOM burst ID of the alert sequence and notice-type the type of notice. Available notice types are listed in the following table:

Level	Notice type	Packet_Type	Description
N1g	grm-trigger	201	GRM trigger notice with possible raw localization
N1e	eclairs-wakeup	202	ECLAIRs trigger of new potential burst
	eclairs-catalog	203	ECLAIRs trigger on a flaring source of the on-board catalogue
	slewing	204	Updated localisation of ECLAIRs trigger which will lead to a slew of the platform
	not_slewing	205	Updated localisation of ECLAIRs trigger which will not lead to a slew
N2m	mxt-initial_qf#	209	MXT first localisation (only if platform slew)
	mxt-update_qf#	210	MXT updated localisation (maximum updates is 3)
N2v	vt-candidate	211	VT best candidate localisation (only if platform slew)

Note

Each of these notices can only be issued once per alert sequence (apart from the mxt-update that can be issued up to 3 times), thus making the IVORN unique. It is also possible to identify each notice by the Packet_Type value within the notice itself

Common fields

The structure of VOEvents is composed of different XML elements that gather specific information on a detection, such as the event time, localisation, SNR or flux of the source detected, etc. It also provides information on the alert sequence or the satellite configuration details. All SVOM VOEvents contains <Who>, <What>, <WhereWhen>, <How> and potentially <Citations> elements, and share common fields that are described in the table below.

Specific informations depending on the notice type are also added in the <What> element, and described in the subsequent sections.

VOEvent element	Parameter	Value	Description
<Who>	AuthorIVORN	ivo://org.svom/fsc	VO identifier of the SVOM French Science Center responsible for the notice creation
	Date	ISOtime in UTC	Creation time of the notice by the automated pipeline
	Author		Contact information of the FSC
<What>	Packet_Type	int	Notice type identifier (defined above)
	Pkt_Ser_Num		Notice number per Packet_Type
	Instrument	- ECLAIRs - GRM - MXT - VT	Instrument involved
<What> Svom_Identifiers	Notice_Level	see table above	SVOM notice reference identifier
	Burst_Id	sbYYMMDDnn	Identifier of the alert sequence
<What> Detection_Info			Specific information depending on the notice type, see following sections
<What> Target_Info	Galactic_Lon	float [deg]	Localisation in galactic coordinates
	Galactic_Lat
	Sun_Angle	float [deg]	Angular distance between the target and the Sun/Moon in geocentric coordinates
	Moon_Angle
<What> Satellite_Info	Sat_Attitude_Ra	float [deg]	Platform attitude in Euler angles
	Sat_Attitude_Dec
	Sat_Attitude_Roll
	Sat_Position_Lat	float [deg]	Satellite position in the Sky in geodetic coordinates
	Sat_Position_Lon
	Sat_Position_Alt	float [km]
<WhereWhen>	Time	ISOtime in UTC	Time of the trigger
	Ra	float [deg]	Localisation of the detection
	Dec
	Error2Radius		R90 uncertainty radius
<How>	Reference		link to a description of the instrument that detected the event
<Citations>	EventIVORN	list of IVORNs	List of previouly published notice refering to the same event
	cite	- followup - retraction	Specify for each cited notice if the current one add information or retract the detection