The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. The Zeeman splitting measurement is the only method to estimate the magnetic field strength along the line of sight directly. The correlation between magnetic field strength and hydrogen column density provides a unique insight into discerning whether and where magnetic fields possess the strength to support gravitational contraction within clouds. Recent observations of OH absorption toward pulsars raise the possibility that the magnetic field strength estimates derived from Zeeman splitting in OH absorptions may be influenced by the angular sizes of background sources. We propose the continued monitoring of four pulsars exhibiting OH absorptions and observe two new pulsars located behind the molecular cloud regions where Zeeman detections of OH absorptions have been identified to constrain the magnetic field strength in quiescent molecular clouds with a characteristic spatial scale of several AUs for the first time, thus shedding light on the physics of star formation and the interstellar medium.

The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. The Zeeman splitting measurement is the only method to estimate the magnetic field strength along the line of sight directly. The correlation between magnetic field strength and hydrogen column density provides a unique insight into discerning whether and where magnetic fields possess the strength to support gravitational contraction within clouds. Recent observations of OH absorption toward pulsars raise the possibility that the magnetic field strength estimates derived from Zeeman splitting in OH absorptions may be influenced by the angular sizes of background sources. We propose the continued monitoring of four pulsars exhibiting OH absorptions and observe two new pulsars located behind the molecular cloud regions where Zeeman detections of OH absorptions have been identified to constrain the magnetic field strength in quiescent molecular clouds with a characteristic spatial scale of several AUs for the first time, thus shedding light on the physics of star formation and the interstellar medium.

The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. The Zeeman splitting measurement is the only method to estimate the magnetic field strength along the line of sight directly. The correlation between magnetic field strength and hydrogen column density provides a unique insight into discerning whether and where magnetic fields possess the strength to support gravitational contraction within clouds. Recent observations of OH absorption toward pulsars raise the possibility that the magnetic field strength estimates derived from Zeeman splitting in OH absorptions may be influenced by the angular sizes of background sources. We propose the continued monitoring of four pulsars exhibiting OH absorptions and observe two new pulsars located behind the molecular cloud regions where Zeeman detections of OH absorptions have been identified to constrain the magnetic field strength in quiescent molecular clouds with a characteristic spatial scale of several AUs for the first time, thus shedding light on the physics of star formation and the interstellar medium.

The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. The Zeeman splitting measurement is the only method to estimate the magnetic field strength along the line of sight directly. The correlation between magnetic field strength and hydrogen column density provides a unique insight into discerning whether and where magnetic fields possess the strength to support gravitational contraction within clouds. Recent observations of OH absorption toward pulsars raise the possibility that the magnetic field strength estimates derived from Zeeman splitting in OH absorptions may be influenced by the angular sizes of background sources. We propose the continued monitoring of four pulsars exhibiting OH absorptions and observe two new pulsars located behind the molecular cloud regions where Zeeman detections of OH absorptions have been identified to constrain the magnetic field strength in quiescent molecular clouds with a characteristic spatial scale of several AUs for the first time, thus shedding light on the physics of star formation and the interstellar medium.

The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. The Zeeman splitting measurement is the only method to estimate the magnetic field strength along the line of sight directly. The correlation between magnetic field strength and hydrogen column density provides a unique insight into discerning whether and where magnetic fields possess the strength to support gravitational contraction within clouds. Recent observations of OH absorption toward pulsars raise the possibility that the magnetic field strength estimates derived from Zeeman splitting in OH absorptions may be influenced by the angular sizes of background sources. We propose the continued monitoring of four pulsars exhibiting OH absorptions and observe two new pulsars located behind the molecular cloud regions where Zeeman detections of OH absorptions have been identified to constrain the magnetic field strength in quiescent molecular clouds with a characteristic spatial scale of several AUs for the first time, thus shedding light on the physics of star formation and the interstellar medium.

The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. It is inherently difficult to measure interstellar magnetic field strengths, with the measurement of Zeeman splitting a unique method to estimate the magnetic field strength along the line of sight directly. Despite the detection of Zeeman splitting in other mediums, there are as yet no Zeeman detections against compact background sources in quiescent molecular clouds or the cold neutral medium. Pulsars with extremely small solid angles and relatively high transverse velocities are ideal background sources to study the magnetic field in molecular clouds, providing a distinct signal to measure splitting against. There are four pulsars with OH absorption detections, namely PSR B1849+00, B1641-45, B1718-35, and B1749-28. We propose to utilize these four pulsars to explore the properties of the magnetic field and its variations within molecular clouds through both the Zeeman splitting of OH absorption and rotation measure estimations, between epochs. If a detection is confirmed, it will open a new window on the hard-to-measure magnetic fields in molecular clouds, independent of interpretation, thus shedding light on the physics of star formation and the interstellar medium.

The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. It is inherently difficult to measure interstellar magnetic field strengths, with the measurement of Zeeman splitting a unique method to estimate the magnetic field strength along the line of sight directly. Despite the detection of Zeeman splitting in other mediums, there are as yet no Zeeman detections against compact background sources in quiescent molecular clouds or the cold neutral medium. Pulsars with extremely small solid angles and relatively high transverse velocities are ideal background sources to study the magnetic field in molecular clouds, providing a distinct signal to measure splitting against. There are four pulsars with OH absorption detections, namely PSR B1849+00, B1641-45, B1718-35, and B1749-28. We propose to utilize these four pulsars to explore the properties of the magnetic field and its variations within molecular clouds through both the Zeeman splitting of OH absorption and rotation measure estimations, between epochs. If a detection is confirmed, it will open a new window on the hard-to-measure magnetic fields in molecular clouds, independent of interpretation, thus shedding light on the physics of star formation and the interstellar medium.

The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. It is inherently difficult to measure interstellar magnetic field strengths, with the measurement of Zeeman splitting a unique method to estimate the magnetic field strength along the line of sight directly. Despite the detection of Zeeman splitting in other mediums, there are as yet no Zeeman detections against compact background sources in quiescent molecular clouds or the cold neutral medium. Pulsars with extremely small solid angles and relatively high transverse velocities are ideal background sources to study the magnetic field in molecular clouds, providing a distinct signal to measure splitting against. There are four pulsars with OH absorption detections, namely PSR B1849+00, B1641-45, B1718-35, and B1749-28. We propose to utilize these four pulsars to explore the properties of the magnetic field and its variations within molecular clouds through both the Zeeman splitting of OH absorption and rotation measure estimations, between epochs. If a detection is confirmed, it will open a new window on the hard-to-measure magnetic fields in molecular clouds, independent of interpretation, thus shedding light on the physics of star formation and the interstellar medium.

The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. It is inherently difficult to measure interstellar magnetic field strengths, with the measurement of Zeeman splitting a unique method to estimate the magnetic field strength along the line of sight directly. Despite the detection of Zeeman splitting in other mediums, there are as yet no Zeeman detections against compact background sources in quiescent molecular clouds or the cold neutral medium. Pulsars with extremely small solid angles and relatively high transverse velocities are ideal background sources to study the magnetic field in molecular clouds, providing a distinct signal to measure splitting against. There are four pulsars with OH absorption detections, namely PSR B1849+00, B1641-45, B1718-35, and B1749-28. We propose to utilize these four pulsars to explore the properties of the magnetic field and its variations within molecular clouds through both the Zeeman splitting of OH absorption and rotation measure estimations, between epochs. If a detection is confirmed, it will open a new window on the hard-to-measure magnetic fields in molecular clouds, independent of interpretation, thus shedding light on the physics of star formation and the interstellar medium.

The magnetic field potentially regulates the process of star formation and the evolution of molecular clouds. It is inherently difficult to measure interstellar magnetic field strengths, with the measurement of Zeeman splitting a unique method to estimate the magnetic field strength along the line of sight directly. Despite the detection of Zeeman splitting in other mediums, there are as yet no Zeeman detections against compact background sources in quiescent molecular clouds or the cold neutral medium. Pulsars with extremely small solid angles and relatively high transverse velocities are ideal background sources to study the magnetic field in molecular clouds, providing a distinct signal to measure splitting against. There are four pulsars with OH absorption detections, namely PSR B1849+00, B1641-45, B1718-35, and B1749-28. We propose to utilize these four pulsars to explore the properties of the magnetic field and its variations within molecular clouds through both the Zeeman splitting of OH absorption and rotation measure estimations, between epochs. If a detection is confirmed, it will open a new window on the hard-to-measure magnetic fields in molecular clouds, independent of interpretation, thus shedding light on the physics of star formation and the interstellar medium.