# Presentation: 130141

## The Monogem Ring: A Nearby SNR Similar to the Local Bubble ?

- Paul Plucinsky
- Smithsonian Astrophysical Observatory

## What is the Monogem Ring ?

-  ROSAT All-Sky Survey, R1+R2 Band, Snowden *et al****.*** 1997
-  large region of enhanced emission in the Galactic anticenter

- Monogem Ring

- LB II 2008

## RASS R1-R7 Band Definitions

-  Snowden *et al.* 1997, R1+R2~C band, R4+R5~M band

- LB II 2008

## Monogem Ring: RASS R1+R2 & R4+R5 Band Images

-  ring of soft X-ray emission with radius ~12.5 degrees, located at (l,b)~(203,+12)
-  little evidence for absorption in the Galactic plane

- LB II 2008

## SNR Models: Plucinsky et al. 1996

| 100 | 22.2 | 9.0 | 2.9 | 0.01 | 78.5 | 12.5 |
| --- | --- | --- | --- | --- | --- | --- |
| 300 | 66.5 | 5.2 | 8.6 | 0.19 | 45.3 | 195.3 |
| 600 | 133.0 | 3.7 | 17.1 | 1.10 | 32.0 | 1104 |
| 1000 | 221.7 | 2.9 | 28.5 | 3.93 | 24.8 | 3961 |
| 1300 | 288.2 | 2.5 | 37.1 | 7.58 | 21.8 | 7633 |

-   D
- (pc)

-   R
- (pc)

-  Age

-  assume remnant is in the adiabatic phase, assume
-  assume CIE model for emission (Raymond & Smith 1977)

- LB II 2008

## Association with PSR 0656+14

-  radio pulsar with a characteristic age of
-  located near center of X-ray ring, proper motion show pulsar is moving away from the Galactic plane (Thomspon & Cordova 1994, Pavlov *et al.* 1996, Mignani *et al.* 2000)

-  parallax measurement by Brisken et al. 2003 determines distance to be D=288+/- 30 pc
-  Chandra LETG (Marshall & Schulz 2002) spectrum determines
-  Thorsett et al. 2003 conclude that the association is firm

- LB II 2008

## High Spectral Resolution X-ray and FUV Observations

-  DXS (Sanders *et al*. 2001, Edgar poster this conference) provided highest resolution spectrum of the Monogem Ring, consistent with low
-  SPEAR (Kim *et al*. 2007 ) provides first FUV image of Monogem Ring , also consistent with low

- DXS Spectrum 148-284 eV

- FIMS/SPEAR C IV Image

- LB II 2008

## Temperature Distribution of the Monogem

- 5.8     <      log (T/K)      <    6.3

-  temperature calculated in 1.28X1.28 degree regions
-  temperature distribution based on CIE model (Raymond & Smith 1977),  DXS data indicate a more complicated model is needed
-  propose 50 ks Suzaku observation at highest temperature region

- Suzaku Pointing

- LB II 2008

## Suzaku XIS1(BI CCD) Spectrum

-  tbabs(vapec) + tbabs(pow), kT=0.20 keV, O abundance =0.5 x solar
-  Reduced chi=1.3, DOF=130

- LB II 2008

## Comparison to Local Bubble

-  Adopt a D~300 pc for the Monogem and associated model
-  Local Bubble model is multiple SNe separated by 1 Myr (Smith & Cox 2001)

| 0.0052 | 0.2-0.4 |
| --- | --- |
| 0.086 | 3-6 |
| 0.2 | 2-3 |
| 4.5 | 1.0-1.8 |

-  Age

- Monogem

- LB

*** ** Numbers for LB model will change if some of the emission is attributed to SWCX

- LB II 2008

## Conclusions

-  If one accepts the association with PSR 0656+14, the Monogem Ring is a nearby bubble of hot gas, D~300 pc
-  The Monogem Ring appears to be a younger, less-energetic explosion into a lower ambient density medium than the Local Bubble
-  high spectral resolution observations with adequate angular resolution are needed to properly characterize the conditions in the plasma of the Monogem Ring

- LB II 2008