Integral field unit (IFU) is an optical instrument that combines spectrographic and imaging powers. Using IFU, the signal from each detector pixel is passed on into a spectrograph which then generates a spectrum for the individual pixel, hence providing spectral information over a 2D field of view. The 3D product of IFU spectroscopy enables us to study objects more effectively in high resolution.
IFU spectroscopy has revived the supernova remnants (SNRs) research at optical wavelength and has shown its incredible potential, some of the highlights are:
- the 3D reconstructions of SNRs structure (Vogt et al. 2017, Martin et al. 2021)
- the discovery of new elements in SNR ejecta (Seitenzahl et al. 2018, Seitenzahl et al. 2019)
- the discovery of previously unknown compact remnant in the SNR 1E0102.2-7219 (Vogt et al. 2018)
Vela Jr. and its Central Compact Object
G266.2-1.2 or Vela Jr. is a young shell-type SNR that lies along the same line of sight as the larger Vela SNR. It is a young SNR with a central compact object (CCO), a member of a unique class of isolated neutron star believed to have low magnetic fields (e.g., De Luca 2017), located at its geometric center (CXO J085201.4−461753; Aschenbach 1998, Pavlov et al. 2001, Kargaltsev et al. 2002).
The nature and physics of CCOs are poorly understood. They are exclusively visible in X-ray and so far, they have no identified counterparts at any wavelength. Our MUSE (Multi Unit Spectroscopic Explorer) data (4750 Å - 9350 Å) of the Vela Jr. field characterized a bubble that is strongly emitting in [N II], at the exact location of the CCO. Together with the recent possible identification of a CCO in SNR 1E0102.2-7219, this is the first time that the CCOs and the interactions with their environment are observed in optical wavelength. This opens a new door for CCO observations outside the X-ray regime.
G266.2-1.2 or Vela Jr. is a young shell-type SNR that lies along the same line of sight as the larger Vela SNR. It is a young SNR with a central compact object (CCO), a member of a unique class of isolated neutron star believed to have low magnetic fields (e.g., De Luca 2017), located at its geometric center (CXO J085201.4−461753; Aschenbach 1998, Pavlov et al. 2001, Kargaltsev et al. 2002).
The nature and physics of CCOs are poorly understood. They are exclusively visible in X-ray and so far, they have no identified counterparts at any wavelength. Our MUSE (Multi Unit Spectroscopic Explorer) data (4750 Å - 9350 Å) of the Vela Jr. field characterized a bubble that is strongly emitting in [N II], at the exact location of the CCO. Together with the recent possible identification of a CCO in SNR 1E0102.2-7219, this is the first time that the CCOs and the interactions with their environment are observed in optical wavelength. This opens a new door for CCO observations outside the X-ray regime.
Initial Results and Discussions
The Vela Jr. CCO field was observed with MUSE mounted on the ESO Very Large Telescope in Wide Field Mode with Ground Layer Adaptive Optics (Bacon et al. 2010). Our data confirms with certainty that the bubble which previously have been identified as Hα nebula (Pellizzoni et al. 2002, Mignani et al. 2007), shines primarily in [N II]. We identify a faint rim of Hα on the bubble and emissions from [S II] and [S III], along with [N I], He I, [Ar III], and [Fe II]. The MUSE data shows that the [N II] abundances are way much stronger than Hα, also virtually there is no [O III] emissions.
We inspected the full MUSE cube and fitted all the spectra of the spaxels that are associated with the bubble.
The Vela Jr. CCO field was observed with MUSE mounted on the ESO Very Large Telescope in Wide Field Mode with Ground Layer Adaptive Optics (Bacon et al. 2010). Our data confirms with certainty that the bubble which previously have been identified as Hα nebula (Pellizzoni et al. 2002, Mignani et al. 2007), shines primarily in [N II]. We identify a faint rim of Hα on the bubble and emissions from [S II] and [S III], along with [N I], He I, [Ar III], and [Fe II]. The MUSE data shows that the [N II] abundances are way much stronger than Hα, also virtually there is no [O III] emissions.
We inspected the full MUSE cube and fitted all the spectra of the spaxels that are associated with the bubble.
Conclusion and Bonus!
The new observations of Vela Jr. with MUSE provide a better spatial resolution of the CCO bubble and a clearer view of the emission lines associated with the bubble. Our data confirm the bubble to be strongly emitting in [N II] instead of being the previously thought Hα nebula. Our initial results show that the [N II] bubble must has a line of sight velocity of 60-80 km/s.
With this new data, we would be able to:
- provide reliable flux calibration and much better spatial maps of the bubble.
- assess the connection between the bubble and the CCO, thus constrain the nature of the CCO.
In our MUSE field, we see a young stellar object (YSO) associated with a nearby emission line star, which was not identified previously. The parallax distance of the star was measured by GAIA and if we can confirm that the YSO is associated with Vela Jr. CCO, it would allow us to determine a reliable distance to the Vela Jr. SNR. This would make Vela Jr. the first Galactic SNR with the most precisely-measured distance.
The new observations of Vela Jr. with MUSE provide a better spatial resolution of the CCO bubble and a clearer view of the emission lines associated with the bubble. Our data confirm the bubble to be strongly emitting in [N II] instead of being the previously thought Hα nebula. Our initial results show that the [N II] bubble must has a line of sight velocity of 60-80 km/s.
With this new data, we would be able to:
- provide reliable flux calibration and much better spatial maps of the bubble.
- assess the connection between the bubble and the CCO, thus constrain the nature of the CCO.
In our MUSE field, we see a young stellar object (YSO) associated with a nearby emission line star, which was not identified previously. The parallax distance of the star was measured by GAIA and if we can confirm that the YSO is associated with Vela Jr. CCO, it would allow us to determine a reliable distance to the Vela Jr. SNR. This would make Vela Jr. the first Galactic SNR with the most precisely-measured distance.