Nobeyama Radio Polarimeters (NoRP)
Analysis Manualver. 2.3
Nobeyama Radio Observatory,
April 1, 2015

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Contents
1 Change Log

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2 Introduction

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3 How to setup

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4 Analysis
4.1 Start Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.1 Event List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.2 Daily Averaged Flux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3 Where is the Data ? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1 Calibrated Data in XDR (IDL save) format . . . . . . . . . . . . . . . . . . . . . .
4.3.2 Raw Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4 Read the Data — Nobeyama Radio Polarimeters . . . . . . . . . . . . . . . . . . . . . . .
4.5 Read the Data — Toyokawa Radio Polarimeters . . . . . . . . . . . . . . . . . . . . . . .
4.6 Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7 Spectrum Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7.1 Optically-Thin Non-Thermal Gyrosynchrotron Emission (Preliminary) . . . . . . .
4.7.2 Optically-Thin Thermal Free-Free Emission (Preliminary) . . . . . . . . . . . . . .
4.8 Example of Analysis Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.8.1 Choose an Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.8.2 Light Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.8.3 Spectrum Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.9 Others . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.9.1 Read Raw Data Directly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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A NoRP data archive: anonymous FTP

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B Acknowledgement

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Change Log• Version 1.0e: 21 December 2000, written by Yokoyama, T.
• Version 2.0e: 7 September 2007, written by Meshalkina, N.
• Version 2.3e: 1 April 2015, modiﬁed by Shimojo, M.

2Introduction

This is a manual for analysis of the data obtained by Nobeyama Radio Polarimeters (NoRP; Nakajima
et al. 1985) and Toyokawa Radio Polarimeters (TYKW; Torii et al. 1979; Shibasaki et al. 1979).
For any questions and requests, please send an e-mail tonorp-help[--at--]solar.nro.nao.ac.jp[--at--] -> @The latest information on NoRP is updated on NRO solar web site. The URL is
http://solar.nro.nao.ac.jp/norp/

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How to setup(1) Installation of the SolarSoftware.
Install the SolarSoftware (SSW) with the subpackage ’Radio/NoRP’. We strongly recommend to
install the SolarSoftware with the sub-packages for Radio/NoRH and Yohkoh/SXT. If these softwares
were not installed, please contact your system manager. The primary distribution site for SolarSoftware
is: http://www.lmsal.com/solarsoft/ We deﬁne the top directory of SSW as ${SSW} and that of NoRP
subpackage as ${NORP} (usually ${SSW}/radio/norp) in this manual.
(2) Installation of NoRP data base
Copy the NoRP data base after getting them from the NoRP data archive at
ftp://solar-pub.nao.ac.jp/pub/nsro/norh/data. The recommended destination is ${NORP}/data.
(3) Setup of your personal environment
Include the followings in your environment setup ﬁle (~/.cshrc).
setenv SSW SSW-directory1
setenv SSW INSTR ‘‘norp’’source ${SSW}/gen/setup/setup.ssw
Note that the enviroment variable ${SSW} can be diﬀerent (Ask your system manager)2 . In case you
analyze many kinds of data at the same time, deﬁne SSW INSTR as follows, e.g.
setenv SSW INSTR ‘‘sxt hxt norh norp’’

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Analysis

4.1

Start Analysis

The NoRP IDL procedures described in this section all depend on the SolarSoftware (SSW). When you
start the analysis, start up the SSW/IDL as follows:
unix% sswidl <CR>
If you start up the SSW/IDL on SDAS, the start-up command is as follows:
unix% SSWidl <CR>

1 /ssw in SDAS
2 In SDAS, it is /ssw

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4.2

Database

4.2.1

Event List

There is a data base for the events (’evx’ data) from January 1990 to May 19923 . In order to list them,e.g. on June 9, 1991 UT,
IDL> norp pr evx,’1991-06-09’ <CR>
From June 5, 1991 UT to June 8,
IDL> st day=’1991-06-05’ <CR>
IDL> ed day=’1991-06-08’ <CR>
IDL> norp pr evx,st day,ed day <CR>
For only strong events which have 1000 SFU peak ﬂux in 17GHz,
IDL> norp pr evx,st day,ed day,criterion=1000 <CR>
4.2.2

Daily Averaged Flux

Daily averaged ﬂux values after choosing non-ﬂaring-time data are installed in the database (after November 1987). These data can be used for obtaining pre-ﬂare ﬂux or for studying the long-term variation.
Toyokawa (1, 2, 3.75, 9.4 GHz) : Nov 1987 – Feb 1994
Toyokawa (3.75 GHz only) : Mar 1994 – Apr 1994
Nobeyama (17, 35, 80 GHz) : Mar 1990 – Feb 1994
Nobeyama (1, 2, 3.75, 9.4, 17, 35, 80 GHz) : May 1994 – Present date
Note that the data for quiet Sun are ﬁxed for 35 GHz (2400 SFU) and 80 GHz (9000 SFU) due to theirinstrumental limits.
In order to read the data, e.g. from Jan 1, 1999 to Jun 30,
IDL> st day=’1999-01-01’ <CR>
IDL> ed day=’1999-06-30’ <CR>
IDL> norp rd avg,st day,ed day,timavg,fiavg,fvavg <CR>
for plot, e.g. of 1GHz
IDL> utplot,timavg,fiavg(0,*) <CR>
of 2GHz
IDL> utplot,timavg,fiavg(1,*) <CR>

4.3

Where is the Data ?

4.3.1

Calibrated Data in XDR (IDL save) format

Some already-calibrated NoRP data are put in the NoRP data archive (see section A). You can obtainthem by anonymous FTP. Before calibration by yourself, try them ﬁrst. They are loaded into the IDL
session by using the IDL command restore. There are 1-sec resolution data for steady observatin and
0.1-sec resolution data for events.
IDL> file=getenv(’NORP XDR’)+’/1999/08/norp19990828 0056.xdr’ <CR>
IDL> restore,file <CR>
IDL> help <CR>
DAY
FI
FIAVG
FREQ
FV
FVAVG
MVD
TIM

STRING
FLOAT
FLOAT
FLOAT
FLOAT
FLOAT
BYTE
STRUCT= ’1999-08-28’= Array[7, 7590]= Array[7]= Array[7]= Array[7, 7590]= Array[7]= Array[7, 7590]= -> ANYTIM2INTS Array[7590]

freq is observing frequencies in units of GHz (in this example, 1, 2, 3.75, 9.4, 17, 3, 80 GHz), tim isobserving time, fi,fv are I (R+L), V (R–L) comonents of ﬂux density and fiavg, fvavg are daily average,
respectively. mvd is an array including the values of unity (1) for valid data or zero (0) for non-valid data.

3 For the events after June 1992, see the event list of Nobeyama Radioheliograph44.3.2

Raw Data

Some raw NoRP data are put in the NoRP data archive (see section A). You can obtain them byanonymous FTP.

4.4

Read the Data — Nobeyama Radio Polarimeters

There are two kinds of formats for Nobeyama Radio Polarimeters (NoRP). One is before uniﬁng with
Toyokawa Radio Polarimeters and the other is after that. For older format, the ﬁles include only 1, 2,
3.75 9.4 GHz data.
In order to read the data into IDL session, give the date (JST) as follows:
IDL> day=’1991-1-25’
IDL> norp rd dat,day,mvd,tim,fi,fv,freq <CR>or give the ﬁle name as follows:
IDL> file=’/archive/pub/norp/raw/1991/01/pl910125’
IDL> norp rd dat,file,mvd,tim,fi,fv,freq <CR>
freq is observing frequencies in units of GHz (in this example, 1, 2, 3.75, 9.4, 17, 3, 80 GHz), tim isobserving time, fi,fv are I (R+L), V (R–L) comonents of ﬂux density, respectively. mvd is an arrayincluding the values of unity (1) for valid data or zero (0) for non-valid data.
In order to read the data in speciﬁed duration:
IDL> timerange=[’1991-1-25 2:00’,’1991-1-25 4:00’] <CR>
IDL> norp rd dat,day,mvd,tim,fi,fv,freq,timerange=timerange <CR>
In order to read the data of speciﬁed frequency, e.g. for 17 GHz,
IDL> rdfreq=[0,0,0,0,1,0,0] <CR>
IDL> norp rd dat,day,mvd,tim,fi,fv,rdfreq=rdfreq <CR>
For 1GHz and 9.4GHz,
IDL> rdfreq=[1,0,0,1,0,0,0] <CR>
IDL> norp rd dat,day,mvd,tim,fi,fv,rdfreq=rdfreq <CR>
Each element in the array rdfreq corresponds to the data of one frequency among 1, 2, 3.75, 9.4, 17, 35
and 80 GHz.

4.5

Read the Data — Toyokawa Radio Polarimeters

The Toyokawa Radio Polarimeters were observing in 4 frequencies, namely 1, 2, 3.75, and 9.4 GHz.
In order to read the data into IDL session, give the date (JST) as follows:
IDL> day=’1992-11-02’
IDL> tykw rd dat,day,mvd,tim,fi,fv,freq <CR>or give the ﬁle name as follows:
IDL> file=’/archive/pub/norp/raw/1992/11/ty921102.01i’ <CR> ; 1GHz I-component
IDL> file0pa=’/archive/pub/norp/raw/1992/11/ty921102.0pa’ <CR> ; 0PA calibration data
IDL> filestt=’/archive/pub/norp/raw/1992/11/ty921102.stt’ <CR> ; status data
IDL> tykw rd dat,file,file0pa,filestt,mvd,tim,data <CR>
freq is observing frequencies in units of GHz, tim is observing time, fi,fv are I (R+L), V (R–L) comonents of ﬂux density, respectively. mvd is an array including the values of unity (1) for valid data or zero(0) for non-valid data.
In order to read the data in speciﬁed duration:
IDL> timerange=’1992-11-2 ’+[’1:00’,’2:00’] <CR>
IDL> tykw rd dat,day,mvd,tim,fi,fv,freq,timerange=timerange <CR>
In order to read the data of speciﬁed frequency, e.g. for 9 GHz,
IDL> rdfreq=[0,0,0,1] <CR>
IDL> tykw rd dat,day,mvd,tim,fi,fv,rdfreq=rdfreq <CR>
For 1GHz and 9.4 GHz,
IDL> rdfreq=[1,0,0,1] <CR>
IDL> tykw rd dat,day,mvd,tim,fi,fv,rdfreq=rdfreq <CR>
Each element in the array rdfreq corresponds to the data of one frequency among 1, 2, 3.75, and 9.4
GHz.

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4.6

Plot

For plotting,
IDL> mfreq=0 <CR>
IDL> norp plot,mfreq,mvd,tim,fi <CR>
where mfreq is the index number of the plotting frequency in the array freq.
To overlay another plot
IDL> mfreq1=1 <CR>
IDL> norp plot,mfreq1,mvd,tim,fi,/over <CR>
Or by directly;
IDL> utplot,tim(where(mvd(mfreq,*))),fi(mfreq,where(mvd(mfreq,*))) <CR>

4.7

Spectrum Analysis

By coordinating multiple frequency observation, we may dervive the spectrum of the emission. The
obtained variable is α whose deﬁnition isFν ∝ ν α .
In real, α is not uniform over the frequencies. But the spectrum in microwave range is approximately
ﬁtted by the fucntion in the form :
[ ( )
]} {
α
( ν )αtk {cν (ν/b
ν αtn −αtkFν ) tk for ν  νbc
Fν = Fν
1 − exp −≈(1)αcν (ν/bνbνbFν ) tn for ν  νb
cν is turn-over ﬂux density, αtk is power index
Here are 4 ﬁtting parameters: νb is turn-over frequency, Fof low frequency side (optically thick side) and αtn is power index of high frequency side (optically thinside), respectively. The procedures are as follows:
IDL> day=’2002-07-18’
IDL> timerange=[’2002-07-18 3:30’,’2002-07-18 4:00’] <CR>
IDL> norp rd dat,day,mvd,tim,fi,fv,freq,timerange=timerange <CR>
IDL> norp rd avg,day,timavg,fiavg,fvavg <CR>
IDL> for m=0,6 do fi(m,*)=fi(m,*)-fiavg(m) <CR>
IDL> norp alpha,freq,fi,mvd,mvdfit,alpha tk,alpha tn,freqpk,fluxpk <CR>
After subtracting the pre-ﬂare ﬂux levels (here daily averages are used), the ﬂare ﬂuxes are given to the
IDL procedure norp alpha. mvdfit is an array including the values of unity (1) for valid data or zero(0) for non-valid data.
Note: The ﬁtting will usually fail in the simple manner shown here. We need (1) to take longer
intergation time for getting better S/N ratio and (2) to remove the inadequate data for ﬁtting (because,say, the emission in that frequency is not due to gyrosynchrotron). See 4.8.3 for better procedures.
4.7.1

Optically-Thin Non-Thermal Gyrosynchrotron Emission (Preliminary)Note: The procedures described in this subsection are under testing. Comments are welcome for improvement.
Based on approximation models, the relation between the physical variables of emitting region andthe emission can be derived. The electron distribution function is assumed to be the power law.
dN V (E)
=K
dE

(

E
E0

)−δ

where E is electron energy (keV), N V (E) is number of electrons (particles) that has larger energy thanE. This distribution is described with parameters δ, E0 , and K. But it is usual to use N V (E0 ) =K/(δ − 1)/E0δ−1 instead of K. And we ﬁx E0 = 10 keV after Dulk (1985).
(a) From Physical Variables to Emission
Inputs; power-law index δ, magnetic ﬁeld strength (G), angle between magnetic ﬁeld and line of sight(degree), and N V — total number (particles) of non-thermal electron (of E > 10 keV): Outputs; ﬂux
density (SFU), circular polarization degree:6

By Dulk’s (1985) method:
IDL> dulk gysy,delta,bb,theta,nv,freq,fi,rc <CR>
If the size of emitting source (by solid angle in unit of sterad) is given additionally, optical depth is also
obtained
IDL> dulk gysy,delta,bb,theta,nv,freq,fi,rc,omega,tau <CR>
By Ramaty’s (1969) method:
IDL> ramaty gysy,delta,bb,theta,nv,freq,fi,rc <CR>
IDL> ramaty gysy,delta,bb,theta,nv,freq,fi,rc,omega,tau <CR>(b) From Emission to Physical Variables
Based on Dulk’s (1985) model we may derive the physical variables from emission. After deriving α(see 4.7), power law index of non-thermal electron distribution function is
IDL> norp alpha,freq,fi,mvd,mvdfit,alpha tk,alpha tn,freqpk,fluxpk <CR>
IDL> norp alpha2delta,alpha tn,delta <CR>
4.7.2

Optically-Thin Thermal Free-Free Emission (Preliminary)Note: The procedures described in this subsection are under testing. Comments are welcome for improvement.
(a) From Physical Variables to Emission
Based on Dulk’s (1985) approximation models, the relation between the physical variables of emitting
region and the emission can be derived. Inputs; electron temperature (K), line-of-site component of magnetic ﬁeld (G), and volume emission measure (cm−3 ) Outputs; ﬂux density (SFU), circular polarization
degree:
IDL> dulk frfr,te,b loc,vem,freq,fi,rc <CR>
If the size of emitting source (by solid angle in unit of sterad) is given additionally, optical depth is also
obtained
IDL> dulk frfr,te,b loc,vem,freq,fi,rc,omega,tau <CR>

4.8

Example of Analysis Session

4.8.1

Choose an Event

Many interesting events are introduced in NoRP web site. It is recommended to access ﬁrst to thesepages. The URL is
http://solar.nro.nao.ac.jp/norp/
4.8.2

Light Curves

After choosing an event for analysis, see the light curves. Calibrated data is already prepared in XDR(IDL save) format for important events. So restore it ﬁrst,
IDL> file=getenv(’NORP XDR’)+’/1999/08/norp19990828 0056.xdr’ <CR>
IDL> restore,file <CR>
For plots,
IDL> mfreq=0 <CR>
IDL> norp plot,mfreq,mvd,tim,fi <CR>
Here mfreq is the number of the data identifying the frequency. For overplotting another frequency data,
IDL> mfreq1=1 <CR>
IDL> norp plot,mfreq1,mvd,tim,fi,/over <CR>
4.8.3

Spectrum Analysis

For deriving spectrum, it is better to integrate longer than default for getting better S/N ratio. In caseintegrating 300 points (30 sec),
IDL> mint=300 <CR>
IDL> norp mkint,mint,mvd,tim,fi,fv,mvdav,timav,fiav,fvav <CR>
Next subtract pre-ﬂare ﬂux
IDL> for m=0,6 do fiav(m,*)=fiav(m,*)-fiavg(m) <CR>
Using this ﬂux, ﬁt the spectrum

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IDL> norp alpha,freq,fiav,mvdav,mvdfit,alpha tk,alpha tn,freqpk,fluxpk <CR>
Assuming gyrosynchrotron emission, the power-law index of non-thermal electrons is obtained
IDL> norp alpha2delta,alpha tn,delta <CR>
Sometimes ﬁtting will fail if the observation data include some points extremely out of the ﬁtting
function. One reason is that the emission mechanism is diﬀerent in the low frequency range ( notgyrosynchrotron but plasma emission ). Another reason is bad S/N ratio in high frequency observation,
especially in 80 GHz. In this case, remove such data points from ﬁtting as follwos:
IDL> mvfreq=[2,3,4,5,6] <CR>
IDL> norp alpha,freq(mvfreq),fiav(mvfreq,*),mvdav(mvfreq,*) $ <CR>
IDL> ,mvdfit,alpha tk,alpha tn,freqpk,fluxpk <CR>
In order to conﬁrm that the ﬁtting is well-done, plot the ﬁtting function over the observation data.
For example, for n-th data
IDL> norp funcp,alpha tk(n),alpha tn(n),freqpk(n) ,fluxpk(n),freqfit,fifit <CR>
IDL> plot,freq,fiav(*,n),/xlog,/ylog,psym=5 <CR>
IDL> oplot,freqfit,fifit <CR>

4.9

Others

4.9.1

Read Raw Data Directly

In order to read raw data directly, for Nobeyama data
IDL> file=’/archive/pub/norp/raw/1991/01/pl910125’ <CR>
IDL> norp rd rdt,file,rdata,date,version <CR>
for Toyokawa data
IDL> file=’/archive/pub/norp/xdr/1992/04/tykw920402.xdr’ <CR>
IDL> tykw rd rdt,file,rdata <CR>
For obtaining observing time (JST) for Nobeyama data
IDL> timej=norp rdt2timej(rdata,date) <CR>A

NoRP data archive: anonymous FTP

The Astronomy Data Center, NAOJ has prepared the anonymous FTP server for the NoRP data archive.
The URL is
ftp://solar-pub.nao.ac.jp/pub/nsro/norp

B

Acknowledgement

We thank the following people. SolarSoftware is a software package for analysis of Solar Data on IDL.
That is supported under various NASA contracts (SXT/EIT/MDI/TRACE/YPOP etc.) and is all in
the public domain. IDL is a product by Research System Inc.

References
Dulk, G. A., 1985, ARAA, 23, 169
Nakajima et al. ”The Radiometer and Polarimeters at 80, 35, and 17 GHz for Solar Observations at
Nobeyama”, PASJ, 37, 163 (1985)
Ramaty, 1969, ApJ, 158, 753
Shibasaki et al. ”Solar Radio Data Acquisition and Communication System (SORDACS) of Toyokawa
Observatory”, Proc. of the Res. Inst. of Atmospherics, Nagoya Univ., 26, 117 (1979)
Torii et al. ”Full-Automatic Radiopolarimeters for Solar Patrol at Microwave Frequencies”, Proc. of theRes. Inst. of Atmospherics, Nagoya Univ., 26, 129 (1979)8